Sandy Bridge CPU Review
Today we have the launch of Intel's new Sandy Bridge architecture which represents a significant shift in technology and is introduced on a 32nm manufacturing process.
Doesn't seem as if much has changed but the all-important clue is in the yellow strip. This tells us that the CPU is a Sandy Bridge one and needs a socket 1155 motherboard.
Sandy Bridge represents a radical shift in architecture with on die graphics.
We have on-chip graphics, new instructions and a performance that can be dynamically adjusted to various thermal envelopes. There are two variants of the chipset to go with the new processors.
The H67 is aimed at users who will deploy a discrete graphics card and variants will support Crossfire and SLI. The P67 is aimed at replacing motherboards with discrete onboard graphics (a cost saving) and supports HDMI 1.4 as well as a host of other useful features.
On the left is the Intel i7-2600K and on the right is the Intel i5-2500K. The K means that the processors are not multiplier locked (expect to pay a premium of $10-25 for the K versions) but as far as we know are not specially selected for their overclocking capabilities any more than the standard variants. The processor lineups for the laptop, handheld/notebook and desktop segments are as follows:
Prices start from a reasonable $225 dollars to over a thousand dollars but with 4 cores and 8 threads and frequencies north of 3GHz they represent hitherto unknown power in the mobile segment.
None of these prices are low enough for budget notebooks but the frequencies are easily enough to blow away Atom or similar processor based notebooks with graphical performance to rival and beat Ion based solutions.
The desktop segment is the one most of us are interested in and here we see a TDP of 95W across the board which is quite impressive given the high clock frequencies. 2 K models are available for overclockers although it is possible to overclock the standard models by adjusting FSB frequency.
The new boxes should make it easy to distinguish Sandy Bridge processors from older variants - the key is the yellow pattern on the newer boxes.
A New Turbo Core
Intel now have Turbo Core 2.0 in their new processors and it is a radical new way of looking at things. Instead of just boosting frequency if only a single core was active, hardware monitoring on the CPU keeps track of the thermal envelope over time and boosts as many cores as needed for as long as thermal headroom permits. This means that good quality cooling can actually increase CPU performance by allowing speeds to be boosted for longer.
There has been a lot of speculation about overclocking the new processors and we think we have fully explored the aspects involved. Firstly, the base speed is set and cannot be increased. Instead, the multipliers for the Turbo Boost speeds can be adjusted. You can also adjust the thermal envelope to higher than the 95W sustained and 120W burst limits that are standard. Motherboard manufacturers may provide additional unlocking fetures but on the boards Intel provided us with, we were restricted to using these settings.
With only a few hours set aside for overclocking we were able to hit 4GHz with 1.15v and 4.5GHz with 1.25v but dared to go no higher with tests still to run. In time, the overclocking community will get to grips with the way these new processors work and we will no doubt see some useful guides for optimising things properly. Until then we can at least conclude that there is a good headroom for enthusiasts to reach high clock speeds.
We used a Corsair H50 which gives the benefits of water cooling with the ease of installation of an air-cooled HSF. In terms of cost and performance it is similar to a high end air cooling solution but without the bulky heatsink or noisy CPU fan. Please not that due to the small reservoir on these sealed budget water block and radiator combo systems they should not be used for extreme overclocking and if the processor temperature gets above 70 degrees Celsius it should be brought back down immediately to prevent water turning to steam and permanently “unsealing” the system.
One of the problems of upgrading Intel processors (not so much if you are buying or building a new system) is the propensity for needing a new motherboard due to socket changes. Going from socket 1156 to 1155 has raised waves of protest from across the PC community. Intel engineers have been keen to explain to us that it is not just a case of blanking out one pin but that a complete redesign was necessary. Things like the processor ring architecture are so complex that they deserve an article of their own and we cannot go into detail here.
Instead we can look at the motherboards whose chipsets were described above.
Firstly, we have the DP67BG aimed at high end users and is equipped with SATA-3 and USB3 (although still not of an intel design). A useful feature is the button on the back to recover from BIOS failure during overclocking etc. and will be handy for many users.
The DH67BL on the other hand is a Mini-ATX form factor and includes HDMI and DVI connectors to allow the graphical capabilities of the processor to be utilised. We tested the output using beta versions of WinDVD and found perfect playback of 1080p content with very low cpu utilisation. Intel pointed out that they also support 3D output but we were not able to test this due to a lack of 3D televisions at our test lab.
All games are tested at the maximum available settings and initially at 1280x1024 so we can be sure of hitting CPU limitations before bandwidth or fill rate ones related to the GPU. We selected Far Cry 2 (first person shooter), HAWX (air combat) and Resident Evil 5 (horror) for our tests as they are newish titles that are suited to benchmarking and make most systems struggle.
The results show that the new processors are much more powerful than competitors and also an interesting reversal of the Whetstone/Drystone trend which is probably due to architetural efficencies. The similarly priced 6 core Thubans just cannot keep up.
The 2600K and 2500K beat all 4-core competitors and are almost as fast as the 6-core competition.
Memory latencies are lower in the new architecture and this allows the dual channel 1333MHz Sandy Bridge processors beat the i7-870 which is using 2000MHz memory.
Everest is a very comprehensive benchmark suite that is set to take the synthetic crown from SiSoft Sandra. We limited our testing to the CPU and FPU benchmarks provided.
CPU Queen is a simple integer benchmark which focuses on the branch prediction capabilities and the misprediction penalties of the CPU. It finds the solutions for the classic "Queens problem" on a 10 by 10 sized chessboard. CPU Photoworx is an integer benchmark that performs different common tasks used during digital photo processing. CPU Zlib is an integer benchmark that measures combined CPU and memory subsystem performance through the public ZLib compression library. CPU ZLib test uses only the basic x86 instructions, and it is HyperThreading, multi-processor (SMP) and multi-core (CMP) aware. CPU AES is an integer benchmark that measures CPU performance using AES (a.k.a. Rijndael) data encryption. It utilizes Vincent Rijmen, Antoon Bosselaers and Paulo Barreto's public domain C code in ECB mode.
The new processors are clearly in the lead in all categories but have an astounding 10-fold performance improvement due to hardware encryption functions.
The FPU Julia benchmark measures the single precision (also known as 32-bit) floating-point performance through the computation of several frames of the popular "Julia" fractal. The code behind this benchmark method is written in Assembly, and it is extremely optimized for every popular AMD and Intel processor core variants by utilizing the appropriate x87, 3DNow!, 3DNow!+ or SSE instruction set extension.
The FPU Mandel benchmark measures the double precision (also known as 64-bit) floating-point performance through the computation of several frames of the popular "Mandelbrot" fractal. The code behind this benchmark method is written in Assembly, and it is extremely optimized for every popular AMD and Intel processor core variants by utilizing the appropriate x87 or SSE2 instruction set extension.
The FPU SinJulia benchmark measures the extended precision (also known as 80-bit) floating-point performance through the computation of a single frame of a modified "Julia" fractal. The code behind this benchmark method is written in Assembly, and it is extremely optimized for every popular AMD and Intel processor core variants by utilizing trigonometric and exponential x87 instructions.
Things are closer here and the Thubans retain their advantage.
Of much more interest to gamers is 3D Mark Vantage and this is the de facto standard for synthetic 3D graphics benchmarks for a wide variety of gaming types. 3D Mark 2011 has just been released and will be incorporated into future tests.
3D Mark scores are quite close with the 4-core Sandy Bridge chips pulling ahead of their 6-core rivals.
The CPU score is of most interest to us and here we can see something quite unusual. The scores are about 50% higher on a per clock basis than the i7-870 and this shows that the new architecture is indeed more efficient.
The only purpose of the GPU benchmark component is to show that even a single core can make full use of our Radeon 5850 card. We would really like to return to this benchmark when we can get our hands on dual Radeon 6970 cards to see just how cpu limited we are by feeding high end Crossfire / SLI setups.
Due to Intel moving forward the release date by two days, we have not been able to extensively test the onboard graphics capabilities on the new Sandy Bridge processors. There are two GPU cores, the 2000 and 3000 depending on the model of CPU. The 3000 is approximately twice as powerful as the 2000 core. As a rough guide we found that the onboard graphics were at least as good as a Radeon HD5450 making low end discrete graphics cards completely unnecessary and particularly appealing to HTPC builds.
The test that most readers will be waiting for is
3D gaming and we now look at how many of the usual suspects fare on Intel's new
3D gaming and we now look at how many of the usual suspects fare on Intel's new architecture..
The new processors are clear winners at all resolutions staying above the key 60fps mark.
Performance is virtually identical across
differing resolutions. The Thubans put in a good show and it seems that HAWX is
capable of taking advantage of more than 4 cores.
While playable on any of the processors, Intel's Sandy Bridge offerings are twice as fast as their competitors and we cannot explain why they are so much faster than the i7-870..
Intel have raised the bar once again with their new architecture. Already the performance leaders they have extended that lead but more importantly have done it at a lower price point. AMD had lower performance at a lower price - now they just have lower performance. Worse still, the onboard graphics are better than AMDs entry level discrete offerings and will cost sales in this lucrative mass market segment. The only thing going for AMD at present is their current installed base and the fact that they have stuck with a single socket for years and anyone upgrading can simply swap out their processors for a faster one.
The i7-2600K and the i5-2500K represent excellent value for money with top end performance without the "extreme" price tag and may be a new strategy by Intel to gain market share. AMD need to release their next generation architecture so we can see how it fares. Until then it is difficult to see how anyone buying or building a new PC would not choose Intel.
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