In 2011, we expected to see three major events: Intel LGA 1155 in the beginning, AMD Bulldozer in the middle and Intel LGA 2011 closer to the end. The first happened as planned (quad-core processors for LGA 1155 arrived in January, with dual-core models coming in the spring and summer) and quickly dominated the market. AMD Bulldozer was pushed to the fall, gave birth to a new platform and was finally introduced. Many had expected a revolution but it didn't happen. Many other users liked its reserve for the future and that AMD had fixed certain Stars issues. Other that that AMD did a nice job finally implementing the long-advertised Fusion strategy — hybrid APUs with a decent CPU part and excellent integrated graphics. In other words, the year was rich with events, and now it's time to take a look at the latest offering, Intel LGA 2011.
Everything has been clear about this one, unlike LGA 1155 and Bulldozer. Intel hasn't planned any world-shattering achievements. Early this year, the company somewhat limited the LGA 1155 platform by the upper threshold of $350 (and the number of cores by four), leaving some leeway for the old LGA 1366. Obviously, after the first tests of Sandy Bridge, everyone understood that some replacement for the latter was in order. So here we got it now: the LGA 2011 platform.
But, in fact, the new platform has little in common with LGA 1366. It's much closer to LGA 1156/1155, having the same dual-chip layout (desktop solutions), the processor being completely fused with the Northbridge. However, this part is added to the sever LGA 1567, from which the novelty inherits support for multiprocessor configurations and a quad-core memory controller. Although LGA 1567 isn't going anywhere yet, so Sandy Bridge-EX (or Xeon E5 4xxx) will only arrive the next year, with only up to eight cores at that to avoid competition with other Intel products. In its turn, Sandy Bridge-E (Core i7-3000) and Sandy Bridge-EP (Xeon E5 2000) are slated for release this year, because LGA 1366 has been around for too long, with its tri-channel memory controller and tri-chip layout (desktop solutions).
But whereas SB-EP will be octacore, two of the three extreme desktop SB-E models will remain hexacore. The last one, Core i7-3820, is even quad-core, resembling Core i7-2700K in specifications, except L3 cache capacity and packaging. Such a "poor man's SB-E," but it still give you access to all platform's advantages.
And there are some, mind you. For example, 40 PCIe lanes, enabling Triple SLI and Quad CrossFire. If two graphics cards are installed, each will have 16 lanes — something impossible on LGA 1155 without additional means and somewhat limited on LGA 1366. The maximum memory capacity has increased as well. The quad-channel controller lets you fill eight memory sockets almost without hindering stability at full clock rate. This means as many as 64GB of RAM in your PC. At that, 32GB will cost you less than on LGA 1155, because you'll be able to buy regular 4GB modules instead of more expensive 8GB ones. Moreover, unlike LGA 1366 (but like LGA 1155), LGA 2011 has full chipset support for a couple of SATA-600 ports.
You can clearly see two locked physical cores.
Not that Intel has ever concealed that, though.
Obviously, you won't lose any of these advantages if you use two high-end CPUs in the series. Just the opposite, you'll also get unlocked multipliers and more cores. We'll talk about Core i7-3900 in details later, for now we'll just note that both are hexacore. Same as Core i7-900 on Gulftown, which means Intel's desktop processors haven't had the number of cores increased. It's just that for the last 10 months the company has been offering either the new architecture with four cores or the old architecture with six cores. This made it difficult to choose, because Sandy Bridge won in few-thread applications (most desktop software), but still lost to the raw power of older solutions in certain tasks. But now you don't have to choose between smart and beautiful — the new Core i7-3900 are both Sandy Bridge and hexacore. That's evolution for you.
Testbeds
CPU |
Core i7-2600 |
Core i7-990X |
Core i7-3930K |
Core i7-3960X |
Core |
Sandy Bridge QC |
Gulftown |
Sandy Bridge-E |
Sandy Bridge-E |
Process technology |
32 nm |
32 nm |
32 nm |
32 nm |
Core clock rate (std/max) |
3.4/3.8 GHz |
3.47/3.73 GHz |
3.2/3.8 GHz |
3.3/3.9 GHz |
Initial multiplier |
34 |
26 |
32 |
33 |
Turbo Boost scheme |
4-3-2-1 |
2-1-1-1-1-1 |
6-5-4-3-2-1(?) |
6-5-4-3-2-1(?) |
Cores/threads |
4/8 |
6/12 |
6/12 |
6/12 |
L1 cache, I/D |
32/32 KB |
32/32 KB |
32/32 KB |
32/32 KB |
L2 cache |
4x256 KB |
6x256 KB |
6x256 KB |
6x256 KB |
L3 cache |
8 MB |
12 MB |
12 MB |
15 MB |
Uncore clock rate |
3.4 GHz |
2.66 GHz |
3.2 GHz |
3.3 GHz |
RAM |
2xDDR3-1333 |
3xDDR3-1066 |
4xDDR3-1333 |
4xDDR3-1333 |
Graphics core |
GMA HD 2000 |
- |
- |
- |
Socket |
LGA 1155 |
LGA 1366 |
LGA 2011 |
LGA 2011 |
TDP |
95 W |
130 W |
130 W |
130 W |
Today, we'll test two new and two old processors. We don't have Core i7-3820 yet, but you shouldn't expect anything too interesting from it anyway. In turn, Core i7-3930K and Core i7-3960X are very interesting. As you can see, these two differ in terms of L3 cache, so you can't turn the junior into the senior despite unlocked multipliers.
Also note that the clock rate of the new extreme CPU is lower than that of the old one. We don't know the Turbo Boost for sure yet, but "6-5-4-3-2-1" seems most reasonable. This means with all cores fully loaded Core i7-3960X's clock rate will be 200 MHz lower than that of 990X (3.4 vs. 3.6). Let's remember this for it might play a role. Under partial load Core i7-3900 processors do very well, because Turbo Boost is very aggressive, almost like that of Core i7 for LGA 1156. One core can overclock up to 600 MHz, so 3930K catches up, and 3960X outperforms, even Core i7-2600, not to mention 990X.
|
Motherboard |
RAM |
LGA 1155 |
Biostar TH67XE (H67) |
Corsair Vengeance CMZ8GX3M2A1600C9B (2x1333; 9-9-9-24) |
LGA 2011 |
ASUS P9X79 Pro (X79) |
16GB 4x1333; 9-9-9-24 |
LGA 1366 |
Intel DX58SO2 (X58) |
12GB 3x1333; 9-9-9-24 |
The memory choice is simple: four modules for the quad-channel controller and three for the tri-channel one. The clock rate is the same across all configurations. LGA 1366 should officially have 1066 MHz, but it's automatically boosted up to 1333 MHz, because the uncore clock rate is 2.66 GHz, and we don't mess with that. For LGA 1155 DDR3-1333 is official. For LGA 2011 the official memory clock rate is 1600 MHz, but our set of 8GB dual-channel kits decided to work at 1333 MHz. However, it's even better for tests this way. And this doesn't prevent you from overclocking your rig, obviously. LGA 2011 is very much tailored to overclocking, and you can even go with DDR3-2666 on certain motherboards, if you find such memory modules.
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