Given that we so often recommend/get requests for Sandy Bridge builds, and how often we repeat information like '2500K you can overclock, 2500 you can't', I figured it would be helpful to give a short guide on the basic differences between the various Sandy Bridge CPUs.
Any suggestions/help/assistance/feedback is welcome. For example, do you think there's any need to have a quick list of the prices of the major 1155 CPUs? Plus, is it all readable, understandable, correct, etc.?
And, little tidbits like the bit in brackets here 'They are quad-cores (except for one minor iteration).', plus the bit about Pentiums at the bottom. Should they be there or are they just unnecessary?
Anyway, the guide:
Intro
The Sandy Bridge CPUs - specifically, socket 1155 CPUs - are the successors in technology and name to the original series of i3, i5, and i7 Intel CPUs. Overall there is a 10-15% increase in performance, and are similar or lower in cost compared to the equivalent CPU from the previous generation.
1155 CPUs all use dual-channel RAM architecture. This means that you will want to install modules of RAM in pairs or other multiples of two (2x2GB, 2x4GB, 4x2GB, etc.) to get full performance from them.
Only DDR3 RAM works with 1155 CPUs.
Through all three denominations of 1155 CPU, there are three notable letter prefixes
Any suggestions/help/assistance/feedback is welcome. For example, do you think there's any need to have a quick list of the prices of the major 1155 CPUs? Plus, is it all readable, understandable, correct, etc.?
And, little tidbits like the bit in brackets here 'They are quad-cores (except for one minor iteration).', plus the bit about Pentiums at the bottom. Should they be there or are they just unnecessary?
Anyway, the guide:
Intro
The Sandy Bridge CPUs - specifically, socket 1155 CPUs - are the successors in technology and name to the original series of i3, i5, and i7 Intel CPUs. Overall there is a 10-15% increase in performance, and are similar or lower in cost compared to the equivalent CPU from the previous generation.
1155 CPUs all use dual-channel RAM architecture. This means that you will want to install modules of RAM in pairs or other multiples of two (2x2GB, 2x4GB, 4x2GB, etc.) to get full performance from them.
Only DDR3 RAM works with 1155 CPUs.
Through all three denominations of 1155 CPU, there are three notable letter prefixes
- K, S and T.
CPU's with the K suffix have an unlocked multiplier for a maximum Turbo frequency of 57. Non-K CPUs are limited to the Intel specified maximum turbo frequency.
CPU's with the S suffix run at lower base frequencies than the non-S CPU's, however the max turbo frequency is the same for both. All of the S parts run at 65W while the non-S parts are spec'd at 95W.
CPU's with the T suffix run at even lower base frequencies and have lower max turbo frequencies. Because of these lower values, the T CPU's run at 35W or 45W.
i3
The i3s are the dual-core 1155 CPUs. Performance-wise, they compare well to the AMD Phenom II X4 CPUs (except in cases where having more cores is more beneficial - video editing, compiling in programming) but are slightly more expensive.
The 1155 i3s do not have the Turbo feature like the i5 and i7, so none of them can be overclocked.- 2100T-2.5 GHz(35W)
- 2100-3.1 GHz(65W)
- 2105-3.1 GHz(65W)
- 2120-3.3 GHz(65W)
The i5s are the mid-range of the 1155 CPUs in terms of price. They are quad-cores (except for the 2390T). The two most popular 1155 i5 CPUs are the 2500, and the 2500K. However there are numerous other models available for the more budget minded shoppers.
The i5 series is often recommended over the i7s as they are more economical.- 2390T-2.7 to 3.5 GHz(35W)
- 2300-2.8 to 3.1 GHz(95W)
- 2310-2.9 to 3.2 GHz(95W)
- 2400S-2.5 to 3.3 GHz(65W)
- 2405S-2.5 to 3.3 GHz(65W)
- 2400-3.1 to 3.4 GHz(95W)
- 2500T-2.3 to 3.3 GHz(45W)
- 2500S-2.7 to 3.7 GHz(65W)
- 2500-3.3 to 3.7 GHz(95W)
- 2500K-3.3 to 3.7 GHz(95W)
The i7s are the top-end 1155 CPUs, and like the i5s are all quad-cores. The main difference between the i7 and the i5 is that the i7 supports HyperThreading (in essence, having an extra virtual core for each core), whereas the i5s do not.
Like the i5s, there are two major iterations - the 2600, and the 2600K. As before, the latter can be overclocked whereas the former cannot.
One other difference is that the 2600K does not support VT-d (enables guests in virtual machines to directly access devices such as GPUs and HDD controllers).- 2600S-2.8 to 3.8GHz(65W)
- 2600-3.4 to 3.8GHz(95W)
- 2600K-3.4 to 3.8GHz(95W)
Overclocking
Since the option for overclocking is often important in buying a 1155 CPU, here are a few quick notes. Note that this is not a guide to overclocking Sandy Bridge CPUs.- Only two 1155 motherboard chipsets have overclocking abilities - this is P67 and Z68. The H67 chipset does not have the ability to overclock CPUs.
- 1155 CPUs cannot have a multiplier higher than 57 (i.e. 5.7GHz)
- Non-K series CPUs can actually be overclocked, as the multiplier can be increase, though not to as a high a multiplier as K-series CPUs. Non-K CPUs can increase their clock by up to four bins (increments) above their default clock (i.e, the i5 2500 can be overclocked to 3.7GHz).
- Non-K series CPUs can also be overclocked by increasing the BCLK frequency. However, since this measure is responsible for the SATA and PCI-e controllers, increase it by more than a few MHz can cause unstability across the whole system and so isn't recommended.
RRP prices go here, perhaps?
Notes
1155 Pentiums (yes, they do exist) are unlikely to feature in any builds on these forums and so have not been included in this guide.
