Lynnfield - Nehalem Finally Goes Mainstream!

Lynnfield Makes its Long Awaited Debut

Meet Lynnfield, Intel's latest processors that have been on the upcoming horizon for the longest time. The mainstream successor to Intel's Core 2 platform is based on the same 45nm Nehalem CPU microarchitecture as the Core i7 and it has finally arrived after being pushed back from its original July launch date. Much has been speculated about reasons for the delay of Lynnfield to the last quarter of 2009, though the general economic malaise certainly hasn't helped Intel's cause. In any case, we fancy that there should significant pent-up demand for new mainstream processors, what with Windows 7 launching next month.

Physically, these mainstream Lynnfield chips are smaller overall than the current Bloomfield Core i7 models in the market despite having slightly more transistors. The packaging is the reason for the size shrink. With the processor's much lower pin, it doesn't make economical sense to continue using the more expensive LGA1366 socket and its platform. As such the Lynnfield processors use a new socket, LGA1156 coupled with a new platform (which we'll touch upon quite shortly). While they are Nehalem architecture based and have common characteristics like a similar amount of L2 and L3 cache, there have been some significant changes under the hood. Firstly, the integrated tri-channel memory controller has been reduced to a more conventional dual-channel controller that should be adequate for most mainstream users.

Then there's the addition of an integrated PCIe graphics controller with 16 lanes of PCIe 2.0, removing another functionality from the motherboard chipset and bringing it into the processor. Of course, with its mainstream emphasis, some things had to go and the QuickPath Interconnect (QPI) links on the Bloomfield has been removed. One of Intel's older technologies, Direct Media Interface (DMI) is used instead to communicate with the chipset. Along with these changes, the cost of manufacturing has been lowered sufficiently for Intel to price them in the US$200 to US$600 range.

And it will be a new chipset that's doing the talking. Intel's P55 Express chipset, a new single chip design that does away with the North/Southbridge divide is currently the only one supporting the LGA1156 socket. We have previewed some of these P55 motherboards, like the ASUS P7P55 EVO, , the Gigabyte P55-UD6 and the MSI P55-GD80 and we'll be talking more about the Intel DP55KG reference board in a while.

Back to Lynnfield, Intel will be introducing three models this year, with more to follow in 2010. These processors are divided into two series, which is where the branding jargon gets confusing. First, there's the Core i5-750, with a nominal clock speed of 2.67GHz. The other Lynnfield processors however use the Core i7 moniker, the Core i7-870 and i7-860, clocked at 2.93GHz and 2.80GHz respectively.

In case you're wondering, there's a very important reason for this. The lower 700 series will not have HyperThreading as a feature, hence you can expect a maximum of four logical cores. The Core i7 800 series meanwhile will have HyperThreading onboard, though you can choose to disable it in the BIOS. The table below lists some of the important details about these available models:

As you may have noticed from the table, these Lynnfield processors have a Max Turbo Frequency column, which is probably the most significant change from Bloomfield. If you can remember, the Core i7 introduced this feature with the Bloomfield Core i7, where the processor will automatically ramp up the clock speed (increase in the multiplier) when fewer cores are being taxed. Lynnfield brings an enhanced version of this, which we shall elaborate next.

The Enhanced Turbo Boost

What Intel did was to bring its Turbo Boost idea further along. In Bloomfield, one typically can only ramp up the clock speed by one multiplier and at most you'll find it going up by two grades if it's a lightly or singly threaded application. These values for the Turbo Mode multiplier were fixed and one has to get the Extreme Edition Core i7 models, which are unlocked, to set more aggressive multipliers.

The same 'lock' applies for our very 'non-extreme' Lynnfield processors, as we were unable to change the Turbo Boost ratios in the BIOS. What has changed however is the extent of the default multipliers. For instance, the Core i5-750 is clocked at 2.66GHz, rising up to 3.2GHz when only a few cores were taxed, which is an increase of 4 multipliers (every 133MHz is a multiplier given the base clock of 133MHz).

This is quite the jump, especially for older, single threaded applications which hardly benefit from having more processor cores. It is also perhaps, an implicit admission from Intel that the pace of multi-core development has not been reflected in the software arena. Many applications remain constricted to dual-cores, much less than the HyperThreaded future envisioned by Intel.

Hence, this move to bolster Turbo Boost, not only bodes well in the performance stakes, but also for the sake of power efficiency. Obviously, having your processor vary its clock speed aggressively according to the load is the path to optimal power efficiency, since it's more likely to spend the idle moments at lower clock speeds and voltages.

In fact, this whole dynamic clock scaling Turbo Boost feature is limited by the thermal envelope of the processor. For these Lynnfield processors, it is 95 watts and whether one core or four cores are being utilized, the processors will not exceed the TDP threshold. The Lynnfield's new Power Control Unit (PCU) is responsible for tackling this aspect and we've detailed about the PCU's operation during our intimate discussions with Intel back in our Computex trip.

Turbo Boost in Action

We decided to explore how Turbo Boost worked by running various applications and checking the clock speed. The first thing we noticed was that even when the system appeared to be idling, the clock speeds can fluctuate very quickly in a short time span. For the Core i7-870, the idling multiplier seemed to be between 13 and 14x (1.7 ~ 1.8GHz), but it can also hover around the 10x multiplier level if there aren't any background tasks operating as well as your settings utilized in the BIOS to define the processor's operational levels.

To test if Turbo Boost worked as advertised, we first ran AquaMark3, an aging benchmark that's mostly single threaded. We found that our Core i7-870 scaled up to 3.6GHz, its rated maximum in this application. Next, we tried Cinebench 10 with all the cores active. At this full load, the maximum was only around 3.06GHz, (133 x 23), with slight upward fluctuations from time to time. It looked like the Core i7-870 was hitting its TDP limits here in Cinebench and a glance at our power meter confirmed the much higher power draw.

In a game that is supposed to be multi-threaded, like Crysis, we found a similar behavior, with the CPU topping out at 3.06GHz, with occasional moments when it went up to 25x and higher. Testing other applications yielded similar results, with multi-threaded ones hitting a limit at the 23x to 24x multiplier mark.

Looking at our results (which will be shown in our benchmarks), we can roughly generalize that having Turbo Boost enabled will always mean higher performance, though the amount of scaling and performance gain varied from application to application. For sure, we expect this feature to be very useful for power efficiency and likely a key reason to get Lynnfield over Bloomfield.

Intel P55 Express Chipset

Below is the block diagram for the Intel P55 Express chipset that support the Lynnfield processors. As the diagram shows, the memory and graphics controllers are now handled by the processor. While dual-GPU configurations (both NVIDIA SLI and ATI CrossFireX but as usual, certification is required for NVIDIA SLI) are supported on the Lynnfield and P55 Express, there are some limitations compared to that on the previous Core i7 chipset, the X58 Express. Namely, when two graphics cards are installed, the available PCIe lanes for each is in a x8/x8 configuration and not the full x16/x16. (A single GPU of course will be able to use the full 16 lanes for itself). For most mainstream to performance GPUs, this shouldn't be an issue, since they won't ever need all that bandwidth. Even for high-end needs, it's not going to be a world of difference.

The shift of the controller to the processor explains why Intel was able to go with a single chip design for the P55 chipset. With support for six SATA ports, HD audio and Gigabit Ethernet, it's all very ordinary so far. The number of USB ports has increased slightly to 14 from the 12 on the Core i7's X58 Express chipset but unfortunately, those hoping for the next-gen SATA 6 Gbit/s interface will be disappointed that they won't be making an appearance just yet. Perhaps expect later motherboard revisions from the usual suspect to sport this feature. Finally, we also see how DMI is now the path for communication between the chipset and the Lynnfield processor.

The Intel Desktop Board DP55KG Extreme Series

For brevity sake, we'll refer to the board as the "Intel DP55KG". It is but one of four Intel P55 Express motherboards available (the others are the DP55SB, DP55WG and DP55WB) from the vendor for Lynnfield, including two mATX variants (DP55SB and DP55WB). Except for the mATX DP55WB, all these boards support DDR3-1600MHz memory and will come with dual-GPU support. You can expect most of the features listed in the P55 Express chipset to make its way to most of these boards.

For the DP55KG, there are additional features to justify its flagship status, like LED indicators, an extra secondary SATA controller that increases the total number of SATA ports to eight and a handy BIOS reset switch at the rear panel. There's even an integrated Bluetooth module, which is usually not a standard feature on motherboards.

Of course, the new socket LGA1156 means that a compatible cooler is required for the Lynnfield processor. The socket itself is fairly simple to install, with a straightforward lever and locking mechanism while notches on the processor ensure that mistakes are unlikely - similar to both LGA775 and LGA1366. Third party vendors have been preparing LGA1156 coolers and universal coolers that support a variety of sockets are already in the wild.

List of Quad-core Processors

Now that Nehalem has gone mainstream, we have updated our table with the current generation of quad-core offerings from both AMD and Intel:

Test Setup

Since the new Lynnfield processors are targeted at the mainstream, with a price range of less than US$600, we won't be comparing them to the flagship Bloomfield Core i7. Instead, the less powerful models, the Core i7-950 and 920 will be used. We also tested a set of results for the Core i7-870 with Turbo Boost disabled (meaning that it runs at its default 2.93GHz) to find out the impact of that feature on performance.

Intel's older Core 2 quad-cores will also be represented, since Lynnfield is the intended successor for this segment and we'll be using the scores for two of the higher end 45nm Core 2 Quad, the Q9650 and Q9550, since prices for these formerly top processors have fallen heavily since their heyday.

Finally, AMD's Phenom II X4 may be facing its sternest test yet as Intel finally has a competitively priced Nehalem to undermine AMD's value proposition. We'll be showing the top two models, the X4 965 and 955 Black Edition in our benchmarks.

Intel Core i5/i7 (Lynnfield) Test Configuration

• Intel DP55KG (Intel P55 Express chipset)
• 2 x 1GB Kingston HyperX DDR3-1333 (CAS 7-7-7-20)
• Zotac GeForce GTX 260 (ForceWare 178.24)
• Seagate 7200.10 200GB SATA hard drive (one single NTFS partition)
• Windows XP Professional with Service Pack 2
• Intel INF 9.1.1.1015 and Matrix Storage Manager 8.9.0.1023

Intel Core i7 Test Configuration

• Gigabyte X58 Extreme (Intel X58 Express chipset)
• 3 x 1GB Kingston HyperX DDR3-1066 (CAS 7-7-7-20)
• Zotac GeForce GTX 260 (ForceWare 178.24)
• Seagate 7200.10 200GB SATA hard drive (one single NTFS partition)
• Windows XP Professional with Service Pack 2
• Intel INF 9.1.0.1007 and Matrix Storage Manager 8.6.0.1007

Intel Core 2 Quad Test Configuration

• ASUS P5E3 Deluxe (Intel X38 Express chipset)
• 2 x 1GB Kingston HyperX DDR3-1333 memory modules (CAS 7-7-7-20)
• Seagate Barracuda 7200.10 200GB SATA hard disk drive (one single NTFS partition)
• Zotac GeForce GTX 260 (ForceWare 178.24)
• Microsoft Windows XP Professional with Service Pack 2
• Intel INF 8.3.1.1009 and Matrix Storage Manager 7.8.0.1012

AMD Phenom II X4 Test Configuration

• MSI 790FX-GD70 (AMD 790FX + SB750)
• 2 x 1GB Kingston HyperX DDR3-1333 (7-7-7-20)
• Seagate Barracuda 7200.10 200GB SATA hard drive (one single NTFS partition)
• Zotac GeForce GTX 260 (ForceWare 178.24)
• Microsoft Windows XP Professional with Service Pack 2

Benchmarks

The following benchmarks were used in this review:

• BAPCo SYSmark 2007 Preview (ver 1.04)
• Futuremark PCMark 2005 Pro
• Lightwave 3D 7.5
• 3ds Max8 (SP2)
• Cinebench 10
• XMpeg 5.03 (DivX 6.8 encoding)
• Futuremark 3DMark06 v1.1
• AquaMark3
• World in Conflict v1.05
• Crysis v1.1

Results - SYSmark 2007 Preview

Making a splash on its first benchmark, the Core i7-870 showed that its enhanced Turbo Boost was very useful when it emerged fastest in SYSmark 2007. It beat out the Bloomfield Core i7 contenders though once you consider its non-Turbo score, it was behind the Core i7-950. Similarly, with Turbo Boost, the Core i7-750 surpassed the Core i7-920. All the Nehalem processors turned out to be especially strong in the Productivity and 3D sections.

Results - Futuremark PCMark05 Pro

With Turbo Boost, the Core i7-870 manages to edge out the Core i7-950, while the Core i5-750 similarly beat the Core i7-920. It would have been very different if Turbo Boost was disabled however, with the Core i7-870 barely better than the Core i7-920. Competition however came from other sources, like the top Core 2 Quad Q9650 and the Phenom II X4 965, which were rather evenly matched against the i5-750 and i7-870 respectively.

With a higher memory frequency (DDR3-1333MHz) for all the Lynnfield processors, it's perhaps no surprise to find them leading the memory section and dispels any doubts that the dual-channel memory controller will be of any hindrance in all but the most extreme use cases.

Results - Lightwave 3D 7.5

Next in Lightwave, there were more indications of the potency of Turbo Boost. At two threads (Tracer-Radiosity) in particular, there was quite the difference for the Core i7-870 between the results with and without Turbo Boost. It also helped the 870 produce the best score for two threads. Meanwhile, the Core i5-750 seemed to benefit from not having HyperThreading, as at both four and eight threads, it had the best scores among the Lynnfield and was even faster than the Core i7-950.

Looking at the other processors, the Phenom II X4 did quite well in Tracer-Radiosity, with one of the faster timings for two and four threads. This however did not last and in the Sunset test, the Nehalem processors were generally ahead.

Results - 3ds Max 8 (SP2)

It was in this 3D rendering benchmark that the mainstream nature of Lynnfield was exposed. The Bloomfield processors were clearly king here, with even the Core 2 quad-cores posing stiff competition when using Radiosity.

Results - Cinebench 10 and XMpeg 5.0.3 (DivX 6.8 encoding)

Cinebench 10 was another test where the Bloomfield Core i7 reigned supreme and by a substantial amount too. Even the Core i7-920 came in faster than the Core i7-870. With all the cores active, there was negligible improvement for enabling Turbo Boost while without HyperThreading, the Core i5-750 seemed to suffer the most here among the Nehalem CPUs.

In DivX encoding, having Turbo Boost is a must as we saw quite the impressive gain when that was enabled. Generally, all the Intel processors did not differ too much in the time taken for the encoding, with the Core 2 quad-cores remaining competitive. The slower clock speed of the Core i7-920 is probably a reason why it didn't fare too well here, coupled with the lack of the new Turbo Boost to ramp up its clocks.

Results - Futuremark 3DMark06 & AquaMark3

Next, we have two synthetic gaming benchmarks. 3DMark's CPU score was a fair reflection of the specifications of the processors, as the Core i7-950 took the crown and the Core i5-750 was among the slower of the contenders. When it came to the overall score however, the Core i5-750 showed significant improvement. Looking at the jump in scores after enabling Turbo Boost in the Core i7-870, we have no doubt that this feature could be a reason why the Core i5-750 ranked such. The AMD contingent also cannot be dismissed, as the 965 was faster than the Core i7-920 and almost equal to the Core i7-860.

AquaMark3 remains a very lightly threaded application, which explains why the Lynnfield processors dominated the CPU score here, beating the Bloomfields comprehensively. The Core i5-750 was able to win here thanks to Turbo Boost and while the resultant FPS score showed that the CPU score did not mean everything in the final reckoning, it was enough for the 750 to beat the Core i7-920.

Results - World in Conflict & Crysis

When it came to actual 3D games, the Lynnfield processors were roughly equal to the Core 2 quad-cores. Turbo Boost had a slight impact on scores but the Core i7 900 processors were dominant in World in Conflict, though this advantage was reduced in Crysis.

Power Consumption

The Lynnfield comes with a TDP rating of 95W compared to the 130W for Bloomfield so one can expect a lower power draw overall, whether at idle or at full load. Our results confirmed this, with the Core i5-750 having the lowest at idle. Once we started loading the processors, the Lynnfield reached the power draw levels of the Core 2 quad-cores and at full load, they were slightly more power hungry than the Core 2 processors. This put them comfortably lower than both the Bloomfield Core i7 and the high-end Phenom II X4 models.

Overclocking

Next, we tried our hand at overclocking by pushing the base clock from its 133MHz default, as we could not push the multiplier beyond its default (our Lynnfield processors were locked), though one can try lowering the multiplier if the base clock has not reached its overclock limit. Not surprisingly, our best attempt came with the Core i5-750, which allowed us to hit a base clock of 170MHz on the Intel reference board.

It was followed by the Core i7-860 who hit the overclocking barrier at 160MHz. Meanwhile, our luck with the Core i7-870 came to an abrupt end at 150MHz, only a slight bump in terms of the base clock. However, once you factor in the 22x multiplier for the i7-870, it's 3.30GHz, not taking in account Turbo Boost yet. For the i7-860, that translated to 3.36GHz while for the i5-750, it was 3.4GHz, which meant that all three had similar limits.

No doubt, once Turbo Boost comes into play, you're likely to find these processors running at even higher clocks automatically with 4GHz almost a certainty especially for single threaded applications.

Conclusion

Before this review, we had to ask ourselves if the Lynnfield is the promised mainstream savior for Intel's Nehalem, which despite its gee-whiz technological features, has been too costly and generally overpowered as a platform for the average user. The answer from these three Lynnfield processors today is a yes. It's not a resounding endorsement if that's what you're looking for but by staying mostly competitive in our benchmarks with the less powerful Bloomfield Core i7 models, these Lynnfield processors have made their mark.

With the enhanced Turbo Boost kicking in, the highest rated Lynnfield, the Core i7-870 quite often surpassed the Core i7-920 and even the 950 at times. It's much closer between the i5-750 and the i7-920 but with the exception of certain rendering and gaming benchmarks, the 750 came out tops or equal with the 920. The dynamic clock scaling also helps to improve the performance-power efficiency of these chips, which already benefit from a lower 95W TDP. For the first time, we've a multi-core processor which is clever enough to efficiently use its resources effectively, the PCU is ensuring you get the most bang for the buck without any user intervention. For this, we're awarding the Most Innovative Product award for the new Lynnfield processors.

Intel too knows exactly where to price them, putting them in the vicinity of the retail prices for the Core i7-950 (US$569) and 920 (US$279). In particular, the Core i5-750 at US$199 (albeit for 1k units) is mighty close while in terms of relative value, the Core i7-860 at US$285 surely looks more attractive than the US$555 Core i7-870. Add the expected lower cost of the Intel P55 Express chipset (with a single chip design, there should be some cost savings at least) and the entire Lynnfield platform becomes the serious mainstream contender as intended.

After all that, what do you currently lose going from Bloomfield to Lynnfield? We can name HyperThreading (for Core i5 only), support for 3-way GPU configurations and performance in certain high-end memory intensive tasks, all of which are hardly plus points for the mainstream user. With Lynnfield in town, Intel is definitely setting aside the Core i7-900 series only for the ultimate power users while the rest of us can be pretty much contented with the newcomers.

No doubt, as our benchmarks showed, one can probably still do decently with a Core 2 quad-core but that path is closed with no future prospects. There is room however for prices to fall for these Core 2 quad-cores and also for AMD's Phenom II X4, as they are generally slightly behind the Lynnfield Core i5-750 (which also happens to be the likely market competitor for the US$245 Phenom II X4 965).

It may have taken Intel longer than usual to release the mainstream Nehalem but it has been worth the wait. With more models expected for the two Lynnfield series next year and the mobile version, Clarksfield too in the wings, is it finally time for the next wave of PC upgrades? For us, it certainly sounds like it.

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