P55 Review-gasm

Intel’s new Lynnfield CPU looks like a winner. Its performance is near-as-dammit on a par with the more exotic Bloomfield Core i7 processors. At the same time, it promises to be a whole lot cheaper both as a chip and as an overall platform. OK, the branding is a bit fubar, what with the confusing use of both the new Core i5 and existing Core i7 monikers. But the idea of quad-core Nehalem with added Turbo-tastic goodness and all at a lower price than ever before is a bit of a no-brainer. We want one and we’re pretty sure you’ll want one, too.

Vital Statistics

Gigabyte P55-UD6
Price £202
Manufacturer Gigabyte
Web www.giga-byte.co.uk
Socket LGA1156
CPU support Lynnfield Core i5 and i7
RAM DDR3 memory (dual channel)
Multi-GPU SLI and CrossFire
Price check

MSI P55-GD80
Price £180
Manufacturer MSI
Web uk.msi.com
Socket LGA1156
CPU support Lynnfield Core i5 and i7
RAM DDR3 memory (dual channel)
Multi-GPU SLI and CrossFire
Price check

Asus P7P55D Deluxe
Price £168
Manufacturer Asus
Web uk.asus.com
Socket LGA1156
CPU support Lynnfield Core i5 and i7
RAM DDR3 memory (dual channel)
Multi-GPU SLI and CrossFire
Price check

Branding aside, however, there is one further significant snag. You’re going to need a new motherboard if you want to jump on board the Lynnfield Express. It requires both a new chipset and a new CPU. Lynnfield, you see, is a very different processor from the Bloomfield Core i7, the first CPU based on Intel’s latest Nehalem processor architecture. Sure, Lynnfield and Bloomfield share the same execution cores and hence precisely the same raw processing power. But in terms of what industry wags call platform partitioning, Lynnfield is a very different proposition indeed.

To find out more about its inner workings, we suggest you saunter over to page 54 and peruse our in-depth expose. For our purposes here, however, the basics go something like this: Intel has moved the northbridge chip and all its workings into the very silicon die of Lynnfield itself. In other words, Intel’s new Lynnfield-compatible motherboard chipset, the P55, doesn’t have a northbridge at all. It’s less of a chipset and more of a single chip, now known as the platform controller hub or PCH in Intel’s revised nomenclature. The PCH does the job of the old southbridge chip. So that’s disk controlling, USB support, networking and all that jazz.

All of which newness begs a number of rather pressing questions. For starters, if the northbridge has moved off the motherboard and onto the CPU, does the quality of the chipset and in turn the motherboard matter anymore? How does overclocking work under this new regime. And what about SLI and Crossfire support?

Regarding the first question, well, we have three of the most intriguing new P55 motherboards on test this month, so we’ll soon get to the bottom of that. As for overclocking, in terms of the mechanics of the process, it’s very much the same as the original Bloomfield Core i7, it’s just that it all happens on a single chip rather than tweaking two chips in tandem.

Hence, as with Bloomfield the key interface is no longer the front side bus, but rather the base clock. Again, as with Bloomfield, a base clock of 133MHz is common to all three Lynnfields launching this month. Multiply that figure with the chip’s CPU clock ratio or multiplier and you get the headline operating frequency. In the case of the 2.93GHz Core i7 870, that’s 133MHz times 22.
Of course, things get a little more complicated when you factor in Turbo Mode. Depending on the quality of your cooling as well as the number of active software threads, you might see the ratio automatically increase by up to five steps. However, what you won’t be able to do is manually push the multiplier ratio higher. For the time being, at least, the multiplier remains locked for all but the Extreme Edition Core i7 chips based on the Bloomfield core. For Lynnfield, it’s all about the base clock.

What we can say is that the more highly integrated nature of Lynnfield does not seem to have put a downer on the traditionally spectacular overclocks achieved by both the aging Core 2 and the latest stepping of the Bloomfield Core i7 chips. Lynnfield is very much in the same ballpark. Unexpectedly, however, results do vary.

Moving on to multi-GPU, there are pros and cons to the new Lynnfield architecture. One of the biggest changes sees the PCI Express controller brought onto the CPU itself. On the upside, taking PCI Express away from the motherboard means the likes of NVIDIA will struggle to lock consumers into its own chipsets in order to access SLI multi-GPU scaling. In other words, P55 boards will support both SLI and AMD’s Crossfire technology, which is great news.

On the downside, the Lynnfield PCI Express controller is limited to 16 lanes compared to 40 for the X58 Bloomfield chipset. So, that’s just eight per card in dual-GPU mode. Initially, we’re confident that won’t translate into a performance penalty. But it does raise questions regards the long term viability and upgradeability of Lynnfield and the P55 platform.

If that’s the broader context behind Lynnfield and the P55 chipset, what do the first motherboards look like? All three of our P55 debut trio are serious, enthusiast fare. Admittedly, that does make for hefty prices well north of £100. But it also means they give us a good idea of just what the new Lynnfield-P55 combo is capable of.

First up is the Asus P7P55D Deluxe. It’s a stylish board in the typical Asus idiom. The P55’s single-chip architecture is also immediately apparent. Thanks to the space freed up by the absence of the usual northbridge chip, it’s also a very uncluttered design with between 5mm to 10mm more breathing space between the socket and DIMMs than the other two boards.
It’s also absolutely rammed with features. The biggest head turner is the plug-in TurboV overclocking remote control. It’s designed to provide easy access to both on the fly and pre-stored overclocking settings without the need to jump into the BIOS. We look forward to getting to know just how effective it is, but our early experience suggests that the best results still come from getting down and dirty with the BIOS settings. Enthusiasts are also going to love the P7P55D thanks to DIP switches that allow the various voltage safeguards to be overridden.

In its own very different way, Gigabyte’s P55-UD6 will be just as exciting a prospect for performance junkies. It’s a seriously imposing and expensive, if rather conventional, looking item, stacked with cooling pipes, chunky heat sinks and slick, flush-fitted MOSFETs. In fact, by placing the PCH in the traditional northbridge location, it shares its basic cooling layout with a conventional two-chip board and is therefore a little more cramped around the CPU socket than the Asus.

But the stand-out feature has to be the presence of six memory-DIMM slots. If you’re wondering what devilry has allowed Gigabyte provide three memory channels, think again. What you’re looking at is a dual-channel setup, with three slots per channel. It also sports a Marvell SATA controller with 6GB/s support, handy if you harbour hopes of a super fast SSD array in the future. On the downside, Gigabyte has strewn the power, reset and clear-CMOS switches rather randomly around the board. Not a huge issue, but it does make you wonder whether the scatological engineering has spilled over into areas that could impact performance.

Our final candidate is MSI’s P55-GD80. It’s another big iron board with a mega feature set. Indeed, it has its own very particular take on the enthusiast-friendly vibe. Like the Asus board, it has buttons for tweaking both the base clock and accessing an auto overclocking function. However, MSI has located them directly on the motherboard, rather than a plug in-remote. Whether that’s a better approach is a question of personal taste.
However, what we can say is our first impressions of both features are underwhelming. You still get much better results with manual BIOS tweaking than either the base clock buttons or the OC Genie auto-overclocking switch, despite the fact that the latter is enabled by a dedicated processor chip that is claimed to detect the best clock and voltage settings for both the CPU and memory. The enthusiast community will also welcome the presence of MSI’s V-Kit package which includes voltage check points for the CPU, memory and memory controller along with hardware DIP switches for overriding voltage safe limits. Fiddle with these at your peril.

Anyway, each board has plenty going for it. But which is quickest? At stock clockspeeds, the Asus and Gigabyte boards come out on top thanks to superior management of Lynnfield’s Turbo Boost.

Shift the focus to overclocking and the pecking order changes once again. The Asus and MSI motherboards outpaced Gigabyte’s P55-UD6 by no less than 300MHz. BIOS optimisations and the quality of voltage regulation are probably factors here. In fact, because the performance of the revised Turbo Boost feature can offer up to 666MHz of additional grunt, which is at least partially down to the motherboard’s control, plus the potential for general flakiness that comes with the arrival of any significantly new CPU architecture, you could say motherboards matter more than ever before.

Still, as interesting as this initial trio of P55 boards is, we look forward to more affordable alternatives appearing in the coming months. After all, the most attractive thing about Lynnfield is the prospect of Core i7 performance for Core 2 cash. These boards do prove that there’s plenty of power on offer from the off.