The Sandy Bridge Review: Intel Core i7-2600K, i5-2500K and Core i3-2100 Tested
by Anand Lal Shimpi on January 3, 2011 12:01 AM ESTThe Lineup
I don’t include a lot of super markety slides in these launch reviews, but this one is worthy of a mention:
Sandy Bridge is launching with no less than 29 different SKUs today. That’s 15 for mobile and 14 for desktop. Jarred posted his full review of the mobile Core i7-2820QM, so check that out if you want the mobile perspective on all of this.
By comparison, this time last year Intel announced 11 mobile Arrandale CPUs and 7 desktop parts. A year prior we got Lynnfield with 3 SKUs and Clarksfield with 3 as well. That Sandy Bridge is Intel’s biggest launch ever goes without saying. It’s also the most confusing. While Core i7 exclusively refers to processors with 4 or more cores (on the desktop at least), Core i5 can mean either 2 or 4 cores. Core i3 is reserved exclusively for dual-core parts.
Intel promised that the marketing would all make sense one day. Here we are, two and a half years later, and the Core i-branding is no clearer. At the risk of upsetting all of Intel Global Marketing, perhaps we should return to just labeling these things with their clock speeds and core counts? After all, it’s what Apple does—and that’s a company that still refuses to put more than one button on its mice. Maybe it’s worth a try.
Check Jarred’s article out for the mobile lineup, but on desktop here’s how it breaks down:
| Processor | Core Clock | Cores / Threads | L3 Cache | Max Turbo | Max Overclock Multiplier | TDP | Price |
| Intel Core i7-2600K | 3.4GHz | 4 / 8 | 8MB | 3.8GHz | 57x | 95W | $317 |
| Intel Core i7-2600 | 3.4GHz | 4 / 8 | 8MB | 3.8GHz | 42x | 95W | $294 |
| Intel Core i5-2500K | 3.3GHz | 4 / 4 | 6MB | 3.7GHz | 57x | 95W | $216 |
| Intel Core i5-2500 | 3.3GHz | 4 / 4 | 6MB | 3.7GHz | 41x | 95W | $205 |
| Intel Core i5-2400 | 3.1GHz | 4 / 4 | 6MB | 3.4GHz | 38x | 95W | $184 |
| Intel Core i5-2300 | 2.8GHz | 4 / 4 | 6MB | 3.1GHz | 34x | 95W | $177 |
| Intel Core i3-2120 | 3.3GHz | 2 / 4 | 3MB | N/A | N/A | 65W | $138 |
| Intel Core i3-2100 | 2.93GHz | 2 / 4 | 3MB | N/A | N/A | 65W | $117 |
Intel is referring to these chips as the 2nd generation Core processor family, despite three generations of processors carrying the Core architecture name before it (Conroe, Nehalem, and Westmere). The second generation is encapsulated in the model numbers for these chips. While all previous generation Core processors have three digit model numbers, Sandy Bridge CPUs have four digit models. The first digit in all cases is a 2, indicating that these are “2nd generation” chips and the remaining three are business as usual. I’d expect that Ivy Bridge will swap out the 2 for a 3 next year.
What you will see more of this time around are letter suffixes following the four digit model number. K means what it did last time: a fully multiplier unlocked part (similar to AMD’s Black Edition). The K-series SKUs are even more important this time around as some Sandy Bridge CPUs will ship fully locked, as in they cannot be overclocked at all (more on this later).
| Processor | Core Clock | Cores / Threads | L3 Cache | Max Turbo | TDP |
| Intel Core i7-2600S | 2.8GHz | 4 / 8 | 8MB | 3.8GHz | 65W |
| Intel Core i5-2500S | 2.7GHz | 4 / 4 | 6MB | 3.7GHz | 65W |
| Intel Core i5-2500T | 2.3GHz | 4 / 4 | 6MB | 3.3GHz | 45W |
| Intel Core i5-2400S | 2.5GHz | 4 / 4 | 6MB | 3.3GHz | 65W |
| Intel Core i5-2390T | 2.7GHz | 2 / 4 | 3MB | 3.5GHz | 35W |
| Intel Core i5-2100T | 2.5GHz | 2 / 4 | 3MB | N/A | 35W |
There are also T and S series parts for desktop. These are mostly aimed at OEMs building small form factor or power optimized boxes. The S stands for “performance optimized lifestyle” and the T for “power optimized lifestyle”. In actual terms the Ses are lower clocked 65W parts while the Ts are lower clocked 35W or 45W parts. Intel hasn’t disclosed pricing on either of these lines but expect them to carry noticeable premiums over the standard chips. There’s nothing new about this approach; both AMD and Intel have done it for a little while now, it’s just more prevalent in Sandy Bridge than before.
More Differentiation
In the old days Intel would segment chips based on clock speed and cache size. Then Intel added core count and Hyper Threading to the list. Then hardware accelerated virtualization. With Sandy Bridge the matrix grows even bigger thanks to the on-die GPU.
| Processor | Intel HD Graphics | Graphics Max Turbo | Quick Sync | VT-x | VT-d | TXT | AES-NI |
| Intel Core i7-2600K | 3000 | 1350MHz | Y | Y | N | N | Y |
| Intel Core i7-2600 | 2000 | 1350MHz | Y | Y | Y | Y | Y |
| Intel Core i5-2500K | 3000 | 1100MHz | Y | Y | N | N | Y |
| Intel Core i5-2500 | 2000 | 1100MHz | Y | Y | Y | Y | Y |
| Intel Core i5-2400 | 2000 | 1100MHz | Y | Y | Y | Y | Y |
| Intel Core i5-2300 | 2000 | 1100MHz | Y | Y | N | N | Y |
| Intel Core i3-2120 | 2000 | 1100MHz | Y | N | N | N | N |
| Intel Core i3-2100 | 2000 | 1100MHz | Y | N | N | N | Y |
While almost all SNB parts support VT-x (the poor i3s are left out), only three support VT-d. Intel also uses AES-NI as a reason to force users away from the i3 and towards the i5. I’ll get into the difference in GPUs in a moment.
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dgingeri - Monday, January 3, 2011 - link
I have a really good reason for X58: I/OI have 2X GTX 470 video cards and a 3Ware PCIe X4 RAID controller. None of the P67 motherboards I've seen would handle all that hardware, even with cutting the video cards' I/O in half.
This chip fails in that one very important spot. if they had put a decent PCIe controller in it, with 36 PCIe lanes instead of 16, then I'd be much happier.
Exodite - Monday, January 3, 2011 - link
That's exactly why this is the mainstream platform, while x58 is the enthusiast one, though. Your requirements aren't exactly mainstream, indeed they are beyond what most enthusiasts need even.sviola - Monday, January 3, 2011 - link
You may want to look at the Gigabyte GA-P67A-UD5 and GA-P67A-UD7 as they can run your configuration.Nihility - Monday, January 3, 2011 - link
Considering the K versions of the CPUs don't have it.If I'm a developer and use VMs a lot, how important will VT-d be within the 3-4 years that I would own such a chip?
I know that it basically allows direct access to hardware and I don't want to get stuck without it, if it becomes hugely important (Like how you need VT-x to run 64 bit guests).
Any thoughts?
code65536 - Monday, January 3, 2011 - link
My question is whether or not that chart is even right. I'm having a hard time believing that Intel would disable a feature in an "enthusiast" chip. Disabling features in lower-end cheaper chips, sure, but in "enthusiast" chips?! Unless they are afraid of those K series (but not the non-K, apparently?) cannibalizing their Xeon sales?has407 - Monday, January 3, 2011 - link
Relatively unimportant IMHO if you're doing development. If you're running a VM/IO-intensive production workload (which isn't likely with one of these), then more important.Remember, you need several things for Vt-d to work:
1. CPU support (aka "IOMMU").
2. Chip-set/PCH support (e.g., Q57 has it, P57 does not).
3. BIOS support (a number of vendor implementations are broken).
4. Hypervisor support.
Any of 1-3 might result in "No" for the K parts. Even though it *should* apply only to the CPU's capabilities, Intel may simply be saying it is not supported. (Hard to tell as the detailed info isn't up on Intel's ark site yet, and it would otherwise require examining the CPU capability registers to determine.)
However, it's likely to be an intentional omission on Intel's part as, e.g., the i7-875K doesn't support Vt-d either. As to why that might be there are several possible reasons, many justifiable IMHO. Specifically, the K parts are targeted at people who are likely to OC, and OC'ing--even a wee bit, especially when using VT-d--may result in instability such as to make the system unusable.
If Vt-d is potentially important to you, then I suggest you back up through steps 4-1 above; all other things equal, 4-2 are likely to be far more important. If you're running VM/IO-intensive workloads where performance and VT-d capability is a priority, then IMHO whether you can OC the part will be 0 or -1 on the list of priorities.
And while VT-d can make direct access to hardware a more effective option (again, assuming Hypervisor support), it's primary purpose is to make all IO more efficient in a virtualized environment (e.g., IOMMU and interrupt mapping). It's less a matter of "Do I have to have it to get to first base?" than "How much inefficiency am I willing to tolerate?" And again, unless you're running IO-intensive VM workloads in a production environment, the answer is probably "The difference is unlikely to be noticeable for the work [development] I do."
p.s. code65536 -- I doubt Intel is concerned with OC'd SB parts cannibalizing Xeon sales. (I'd guess the count of potentially lost Xeon sales could be counted on two hands with fingers to spare.:) Stability is far more important than pure speed for anyone I know running VM-intensive loads and, e.g., no ECC support on these parts is for me deal killer. YMMV.
DanNeely - Tuesday, January 4, 2011 - link
For as long as MS dev tools take to install, I'd really like to be able to do all my dev work in a VM backed up to the corporate lan to ease the pain of a new laptop and to make a loaner actually useful. Unfortunately the combination of lousy performance with MS VPC, and the inability of VPC to run two virtual monitors of different sizes mean I don't have a choice about running visual studio in my main OS install.mino - Wednesday, January 5, 2011 - link
VMware Workstation is what you need. VPC is for sadists.Even if your budget is 0(zero), and VPC is free, KVM/QEMU might be a better idea.
Also, Hyper-V locally and (via RDP) is pretty reasonable.
cactusdog - Monday, January 3, 2011 - link
If we cant overclock the chipset how do we get high memory speeds of 2000Mhz+? Is there still a QPI/Dram voltage setting?Tanel - Monday, January 3, 2011 - link
No VT-d on K-series? FFFFUUUU!So just because I want to use VT-d I'll also be limited to 6 EUs and have no possibility to overclock?
Then there's the chipset-issue. Even if I got the enthusiast targeted K-series I would still need to get the:
a) ...H67-chipset to be able to use the HD-unit and QS-capability - yet not be able to overclock.
b) ...P67-chipset to be able to overclock - yet to lose QS-capability and the point of having 6 extra EUs as the HD-unit can't be used at all.
What the hell Intel, what the hell! This makes me furious.