Intel Core i7-800 Processor Series
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As you well know, Intel Core i7-900 processors for the LGA1366 socket are not the only Core i7 products in the market. Lynnfield-based solutions for the LGA1156 socket have been selling for over a year now in the mainstream segment, and far better at that. Of course, that core is largely popular because of the Core i5-750 and the very successful Core i5-760, the first "mainstream Nehalems", but still sales volumes inspire certain respect.
What's more important, the two Core i7 series offer similar pricing and specifications, with the exception of Gulftown-based hexacore products which only exist in one series and stand out in both aspects. So it's very interesting to find out whether such "twofold existence" is actually justified. The second reason to review these processors is that the LGA1155 socket is to be rolled out within months, and it's going to replace LGA1156, essentially, offering a number of the matching key features. This means we'll soon need to compare today's test results with the new ones. Well, here you go.
Testbeds
CPU |
Core i7-860 |
Core i7-870 |
Core i7-875K |
Core i7-880 |
Core |
Lynnfield |
Lynnfield |
Lynnfield |
Lynnfield |
Process technology, nm |
45 |
45 |
45 |
45 |
Core clock rate (std/max), GHz |
2.8/3.46 |
2.93/3.6 |
2.93/3.6 |
3.06/3.73 |
Initial multiplier |
21 |
22 |
22 |
23 |
Turbo Boost scheme |
5-4-1-1 |
5-4-2-2 |
5-4-2-2 |
5-4-2-2 |
Cores/HT threads |
4/8 |
4/8 |
4/8 |
4/8 |
L1 cache, I/D, KB |
32/32 |
32/32 |
32/32 |
32/32 |
L2 cache, KB |
4x256 |
4x256 |
4x256 |
4x256 |
L3 cache, KB |
8192 |
8192 |
8192 |
8192 |
Uncore clock, GHz |
2.4 |
2.4 |
2.4 |
2.4 |
RAM |
2xDDR3-1333 |
2xDDR3-1333 |
2xDDR3-1333 |
2xDDR3-1333 |
QPI, GT/s |
4.8 |
4.8 |
4.8 |
4.8 |
Socket |
LGA1156 |
LGA1156 |
LGA1156 |
LGA1156 |
TDP, W |
95 |
95 |
95 |
95 |
Price |
Newegg, Amazon |
Newegg, Amazon |
Newegg, Amazon |
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The Core i7-860 is the junior model, like a year ago. Although its position changed: it used to be one of the most affordable Core i7 products, while now it costs almost like Core i7-870 that got much cheaper. For this reason, buying it has no sense these days, but reviewing it is still interesting. We'll have a Core i5-760 with the same initial clock rate in the next review, so we'll compare these two directly.
The rightmost column needs no introductions. The Core i7-880 is the senior (and expensive) solution. But it's still interesting, because a lot of slower processors have much higher TDP. The Core i7-880 is the top model within the 100W TDP. Well, almost the top, considering certain low-power hexacore Xeons. But those are hardly intended for the home PC budget.
The remaining two models fit in between, being almost identical. We have already mentioned the Core i7-870. It's one of the most affordable and interesting Core i7 products today. The Core i7-875K is the same, but unlocked, which may cost you another $25 or so. Obviously, these two processors should perform the same in the standard mode. We'll see if it's so further in the review.
As you can see from the specifications table, the 860, 870 and 880 model also have different Turbo Boost schemes: it's more aggressive in the higher-end two models. We'll see what it does in real life (another reason to include Core i7-860 into tests).
CPU |
Core i7-950 |
Phenom II X6 1090T |
Core |
Bloomfield |
Thuban |
Process technology, nm |
45 |
45 |
Core clock rate (std/max), GHz |
3.06/3.33 |
3.2/3.6 |
Initial multiplier |
23 |
16 |
Turbo Boost scheme |
2-1-1-1 |
- |
Cores (HT threads) |
4/8 |
6/6 |
L1 cache, I/D, KB |
32/32 |
64/64 |
L2 cache, KB |
4x256 |
6x512 |
L3 cache, KB |
8192 |
6144 |
Uncore clock, GHz |
2.13 |
2.0 |
RAM |
3xDDR3-1066 |
2xDDR3-1333 |
QPI/HT |
4.8 GT/s |
2000 MHz |
Socket |
LGA1366 |
AM3 |
TDP, W |
130W |
125W |
Price |
Newegg, Amazon |
Newegg, Amazon |
The reviewed four will compete with two different processors: Core i7-950 priced similarly to the Core i7-870 (wholesale, of course; retail prices are often different) and having the initial clock rate of the Core i7-880. It also comes with such advantages of the LGA1366 socket as 1.5x as much maximum memory and more PCIe 2.0 lanes. As well as the implying drawbacks: "bulkiness" due to the tri-chip layout and higher power consumption. Something which many users do not care about, though.
The second competitor is the AMD Phenom II X6 1090T, a high-end, but relatively affordable solution. Aside from the price, its advantages include six physical cores. More than similarly priced Intel CPUs can offer. Although the latter support Hyper-Threading, which makes the comparison more diverse. Another less noticeable but important advantage is the platform flexibility. Such processors can be used in machines with multiple graphics cards, each of which will get the full interface width. This is a problem for the LGA1156 socket to say the least, because it requires additional circuity hence higher price. If you don't play games, you can use an AMD CPU with integrated graphics, something impossible for both reviewed Intel platforms. This also makes TDP comparison more ambiguous: a discrete graphics card consumes power and often makes noise. But the performance comparison is very important. After all, entry-level graphics cards are cheap and often have passive cooling, so all these advantages may still be lost if a processor lags behind noticeably. But let's not put the cart before the horse.
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Motherboard |
RAM |
LGA1156 |
Gigabyte P55A-UD6 (P55) |
Kingston KVR1333D3N9K3/6G (2x1333; 9-9-9-24) |
LGA1366 |
Intel DX58SO (X58) |
Kingston KVR1333D3N9K3/6G (3x1066; 8-8-8-19) |
AM3 |
Gigabyte 890FXA-UD7 (AMD 890FX) |
Corsair CM3X2G1600C9DHX (2x1333; 7-7-7-20-1T, unganged Mode) |
For obvious reasons we couldn't equalize the configurations completely. For example, the LGA1366 platform support triple-channel memory configurations, while the other two only work with dual-channel memory. We could have "adjusted" this, but decided not to do it. Most users don't anyway. Of course, as RAM is getting cheaper, 8GB configurations are becoming more and more popular. But that's still more of a trend, not an accomplished fact.
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