Intel's Core i7 870 & i5 750, Lynnfield: Harder, Better, Faster Stronger
by Anand Lal Shimpi on September 8, 2009 12:00 AM EST- Posted in
- CPUs
Multi-GPU SLI/CF Scaling: Lynnfield's Blemish
When running in single-GPU mode, the on-die PCIe controller maintains a full x16 connection to your graphics card:
Hooray.
In multi-GPU mode, the 16 lanes have to be split in two:
To support this the motherboard maker needs to put down ~$3 worth of PCIe switches:
Now SLI and Crossfire can work, although the motherboard maker also needs to pay NVIDIA a few dollars to legally make SLI work.
The question is do you give up any performance when going with Lynnfield's 2 x8 implementation vs. Bloomfield/X58's 2 x16 PCIe configuration? In short, at the high end, yes.
I looked at scaling in two games that scaled the best with multiple GPUs: Crysis Warhead and FarCry 2. I ran all settings at their max, resolution at 2560 x 1600 but with no AA.
I included two multi-GPU configurations. A pair of GeForce GTX 275s from EVGA for NVIDIA:
A coupla GPUs and a few cores can go a long way
And to really stress things, I looked at two Radeon HD 4870 X2s from Sapphire. Note that each card has two GPUs so this is actually a 4-GPU configuration, enough to really stress a PCIe x8 interface.
First, the dual-GPU results from NVIDIA.
| NVIDIA GeForce GTX 275 | Crysis Warhead (ambush) | Crysis Warhead (avalanche) | Crysis Warhead (frost) | FarCry 2 Playback Demo Action |
| Intel Core i7 975 (X58) - 1GPU | 20.8 fps | 23.0 fps | 21.4 fps | 41.0 fps |
| Intel Core i7 870 (P55) 1GPU | 20.8 fps | 22.9 fps | 21.5 fps | 40.5 fps |
| Intel Core i7 975 (X58) - 2GPUs | 38.4 fps | 42.3 fps | 38.0 fps | 73.2 fps |
| Intel Core i7 870 (P55) 2GPUs | 38.0 fps | 41.9 fps | 37.4 fps | 65.9 fps |
The important data is in the next table. What you're looking at here is the % speedup from one to two GPUs on X58 vs. P55. In theory, X58 should have higher percentages because each GPU gets 16 PCIe lanes while Lynnfield only provides 8 per GPU.
| GTX 275 -> GTX 275 SLI Scaling | Crysis Warhead (ambush) | Crysis Warhead (avalanche) | Crysis Warhead (frost) | FarCry 2 Playback Demo Action |
| Intel Core i7 975 (X58) | 84.6% | 83.9% | 77.6% | 78.5% |
| Intel Core i7 870 (P55) | 82.7% | 83.0% | 74.0% | 62.7% |
For the most part, the X58 platform was only a couple of percent better in scaling. That changes with the Far Cry 2 results where X58 manages to get 78% scaling while P55 only delivers 62%. It's clearly not the most common case, but it can happen. If you're going to be building a high-end dual-GPU setup, X58 is probably worth it.
Next, the quad-GPU results from AMD:
| AMD Radeon HD 4870 X2 | Crysis Warhead (ambush) | Crysis Warhead (avalanche) | Crysis Warhead (frost) | FarCry 2 Playback Demo Action |
| Intel Core i7 975 (X58) - 2GPUs | 25.8 fps | 31.3 fps | 27.0 fps | 70.9 fps |
| Intel Core i7 870 (P55) 2GPUs | 24.4 fps | 31.1 fps | 26.6 fps | 71.4 fps |
| Intel Core i7 975 (X58) - 4GPUs | 27.0 fps | 57.4 fps | 47.9 fps | 117.9 fps |
| Intel Core i7 870 (P55) 4GPUs | 24.2 fps | 50.0 fps | 36.5 fps | 116 fps |
Again, what we really care about is the scaling. Note how single GPU performance is identical between Bloomfield/Lynnfield, but multi-GPU performance is noticeably lower on Lynnfield. This isn't going to be good:
| 4870 X2 -> 4870 X2 CF Scaling | Crysis Warhead (ambush) | Crysis Warhead (avalanche) | Crysis Warhead (frost) | FarCry 2 Playback Demo Action |
| Intel Core i7 975 (X58) | 4.7% | 83.4% | 77.4% | 66.3% |
| Intel Core i7 870 (P55) | -1.0% | 60.8% | 37.2% | 62.5% |
Ouch. Maybe Lynnfield is human after all. Almost across the board the quad-GPU results significantly favor X58. It makes sense given how data hungry these GPUs are. Again, the conclusion here is that for a high end multi-GPU setup you'll want to go with X58/Bloomfield.
A Quick Look at GPU Limited Gaming
With all of our CPU reviews we try to strike a balance between CPU and GPU limited game tests in order to show which CPU is truly faster at running game code. In fact all of our CPU tests are designed to figure out which CPUs are best at a number of tasks.
However, the vast majority of games today will be limited by whatever graphics card you have in your system. The performance differences we talked about a earlier will all but disappear in these scenarios. Allow me to present data from Crysis Warhead running at 2560 x 1600 with maximum quality settings:
| NVIDIA GeForce GTX 275 | Crysis Warhead (ambush) | Crysis Warhead (avalanche) | Crysis Warhead (frost) |
| Intel Core i7 975 | 20.8 fps | 23.0 fps | 21.4 fps |
| Intel Core i7 870 | 20.8 fps | 22.9 fps | 21.5 fps |
| AMD Phenom II X4 965 BE | 20.9 fps | 23.0 fps | 21.5 fps |
They're all the same. This shouldn't come as a surprise to anyone, it's always been the case. Any CPU near the high end, when faced with the same GPU bottleneck, will perform the same in game.
Now that doesn't mean you should ignore performance data and buy a slower CPU. You always want to purchase the best performing CPU you can at any given pricepoint. It'll ensure that regardless of the CPU/GPU balance in applications and games that you're always left with the best performance possible.
The Test
| Motherboard: | Intel DP55KG (Intel P55) Intel DX58SO (Intel X58) Intel DX48BT2 (Intel X48) Gigabyte GA-MA790FXT-UD5P (790FX) |
| Chipset: | Intel X48 Intel X58 Intel P55 AMD 790FX |
| Chipset Drivers: | Intel 9.1.1.1015 (Intel) AMD Catalyst 9.8 |
| Hard Disk: | Intel X25-M SSD (80GB) |
| Memory: | Qimonda DDR3-1066 4 x 1GB (7-7-7-20) Corsair DDR3-1333 4 x 1GB (7-7-7-20) Patriot Viper DDR3-1333 2 x 2GB (7-7-7-20) |
| Video Card: | eVGA GeForce GTX 280 |
| Video Drivers: | NVIDIA ForceWare 190.62 (Win764) NVIDIA ForceWare 180.43 (Vista64) NVIDIA ForceWare 178.24 (Vista32) |
| Desktop Resolution: | 1920 x 1200 |
| OS: | Windows Vista Ultimate 32-bit (for SYSMark) Windows Vista Ultimate 64-bit Windows 7 64-bit |
Turbo mode is enabled for the P55 and X58 platforms.
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Genx87 - Tuesday, September 8, 2009 - link
But after looking at the gaming benchmarks. I am wondering if the i5 is worth the cost to upgrade from an E8400? The best I could come up with from the graphs was the Q9560@3Gz or the E8600. In most of the games they were within a few % points. Ill have to see how the i5 does with the new round of cards from AMD\Nvidia before making a decision if I am going to build a new machine or just upgrade the GPU this winter.Kaleid - Tuesday, September 8, 2009 - link
Do like I do. Buy a better GPU. I'll stick to my e8400 at least until the 32nm CPU's arrive.And according to the guru3d review overclocking makes dramatically increases power consumption during load:
"Once we overclock to 4.1 GHz... the power consumption all of a sudden is 295 Watts (!), so an additional 1200 MHz of power is costing us an additional 133 Watts."
http://www.guru3d.com/article/core-i5-750-core-i7-...">http://www.guru3d.com/article/core-i5-7...re-i7-86...
papapapapapapapababy - Tuesday, September 8, 2009 - link
"the lowest Lynnfield is a faster gaming CPU than Intel's fastest dual-core: the E8600"bullshit. the E8600 has higher minimum frame rates umm know "when it matters the most"
http://images.anandtech.com/reviews/cpu/intel/lynn...">http://images.anandtech.com/reviews/cpu/intel/lynn...
scooterlibby - Tuesday, September 8, 2009 - link
Nice review. Lynnfield seems like a great deal too for people building a new system, but from a gaming standpoint, I don't see enough performance difference to upgrade my overclocked e8400 setup. Guess it'll be Sandybridge for me!rbbot - Tuesday, September 8, 2009 - link
What is the maximum memmory you can fit onto a P55 chipset? I notice the Gigabtye board has 6 dimms but their website still says Max 16Gb?Is there a 16Gb chipset limit? Would it increase once those new high-capacity dimms from samsung make an appearance?
the machinist - Tuesday, September 8, 2009 - link
I really don't know what to make of all this. I am about to buy i7 920 and over clock it to 3.6GHZ and then sometime next year upgrade the CPU to i9 6 core on LGA 1366. SLI does not interest me... cores/threads and clock speed are my main concern for 3d rendering.Is there any reason for someone like me to get this new platform instead? Please advice me.
rsher - Tuesday, September 8, 2009 - link
I wish I had an answer for you. I am in the same situation. If you do get a good reply please post it so I could figure out what to buy..BTW what is the i9 CPU?I have some time before I need to upgrade. HAve you considered using the Xenon processors... I use MAX 2010..
rSher
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the machinist - Tuesday, September 8, 2009 - link
rSher Xeon are overkill these days considering the price premium. Single socket CPUs are so powerful these days that I just don't see the bang for the buck when it comes to Xeons. i7 920 over clocked matches some of the mid level Xeons anyway. If I was minting it and rendering only then I would get pair of high end XeonsRegarding your other question....
i9 will be 6 core version that will come out next year and you can use them on LGA1366 Mobos. I think a 8 core version will come out too. They will be expensive but by the time I decide to upgrade they should be less expensive.
PassingBy - Tuesday, September 8, 2009 - link
Can get single socket Xeon machines as well. The reason that professional users often prefer them is for ECC support. Up to you whether that matters for your applications. Naturally, for servers, ECC is the norm and that is also the situation for most professional workstations. Xeons can overclock as well, perhaps sometimes even better than the desktop equivalents, but professional users rarely overclock.Ann3x - Tuesday, September 8, 2009 - link
In some respects a great article. However the assertation that anything below the top end 1336 cpus are pointless is pretty obsurd.As others have stated the headroom and potential overclock of ANY d0 920 easily beats these new processors.
As it is, i7s are aimed at enthusiasts. FOR AN ENTHUSIAST *ie someone willing to tweak and OC* the 920 is still by fast the best bang for buck choice.
The new platform is only better if no tweeking is carried out (ie if youre not a technical user).
Therefore were left with a column aimed at technical users saying something that is only relevant to non technical users. At best its a gross simplification. As worst its missleading.
Yes, the new platform is good for the mass market, yes its exciting. However keep some perspective with your audience, the i7 920 is still BY FAR the best performance value for money CPU if you have the knowledge required to get the most out of it (as the majority of people buying X58 do).