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Phenom II X6 in the lab

by on20 August 2010

amd_phenom_x6_front_small recommended08_75 
Review: Affordable Hexa-Cores

It has been a while since we tested some CPUs. Since about three months AMD is selling it's first Hexa-Core generation, namely the Phenom II X6 1055T and the Phenom II X6 1090T Black Edition. Both CPUs are still manufactured in a 45nm SOI process, but still keeping the TDP envelope of 125W. That's the same TDP as many other Phenom II X4 but with two cores less. We were lucky and got a sample of the new 95W TDP version of the 1055T which is an incredible achievement for AMD to fit six cores in such a TDP.


While Intel upped the L3 cache on its hexa-cores it's the same on the X6 with 6MB. The cores themselves retain their 512kB L2 cache and 64kB L1 caches for data and instructions. With an affordable price point of just €174/$199 for the 1055T and €252/$299 for the 1090T AMD is attacking the lower cost Intel quad-core CPUs such as i5-750 and i5-760. As you can see from the picture of the dice, AMD just added two cores to an existing quad-core but of course tweaked the design. 



MSI 890GXM-E65 (provided by MSI)
AMD 890GX/SB850

MSI 790FX-GD70 (provided by MSI)
AMD 790GX/SB750
ASRock H55M Pro (provided by ASRock)
Intel H55

Intel Pentium G6950, i3-530 (provided by Mindfactory)
AMD Athlon II X2 240e, 245, Phenom II X4 620, Phenom II X6 1090T (provided by AMD)
 AMD Phenom II X6 1055T (95W) (provided by ASRock, we appreciate the superb support)

Scythe Grand Kama Cross (provided by Scythe-Europe)

G.Skill 4GB Kit PC3-12800 (provided by G.Skill)
1067MHz CL7-7-7-20 CR1T 1.30V for Athlon II X2, Pentium G6950
1333MHz CL7-7-7-20 CR1T 1.35V for Athlon II X4, Phenom II X4/X6, i3-530, i5-750

Graphics Card:
MSI R4850-2D1G-OC (provided byMSI)

Power supply:
PC Power & Cooling Silencer 500W (provided by PC Power & Cooling)

Hard disk:
Samsung F1 1000GB RAID-Edition (provided by Ditech)

Case fans:
SilenX iXtrema Pro 14dB(A) (provided by
Scythe DFS122512LS

Cooler Master Stacker 831 Lite (provided by Cooler Master)

All tests are performed with XP SP3. As 64-bit software is still not very common, we stick to the 32-bit version. We will change to Windows 7 when we swap the graphics card for a DX11 capable one.


Overview and Turbo-Core:

The cheapest of AMD hexa-cores the 1055T clocks at 2.8GHz, the just released 1075T will clock at 3GHz and the flagship model starts with 3.2GHz.



The new CPU features Turbo Core, which means the CPU can overclock half its cores up to 400MHz on the 1090T and 500MHz on the 1055T. As long as three or more cores are idle, the CPU speeds up the working cores adding some performance increase especially with single and dual-threaded applications. Many older games will also benefit. We have a screenshot using lamemt, with the 1090T all worked as expected, but the 1055T disappointed. We think this is because our CPU is the new 95W version, so the Turbo can't go up that much otherwise it would exceed the 95W TDP.




First the sad story. Our 1090T does not like overclocking and during the process we scraped three boards. That's also the reason why we could not put on this review much earlier. AMD will send us a replacement but it seems the new CPUs are in such high demand, they can't ship enough of them. So be warned, even if you do not overvoltage other components such as HT or memory controller, even the VCore limit which is reported in the BIOS may cause harm to your board. But we did not expect the CPU to die at "just" 1.5500VCore. The 1055T fared much better, with just 1.4350V which will results in about 1.48VCore reported by CPUz and Everest under load, we managed 3850MHz without a hassle with FSB 275. We did not try to go any higher, because we did not like to scrap another board. Please notice we already got a 95W 1055T, with the currently selling 125W version you may need higher voltages.





Of course it is possible to reduce the VCore to save some energy. Depending on the board you can go down from the 1.3000V of the 1095T to 1.2000V to 1.2250V. As long as Turbo-Core is active, during Turbo the VCore will raise to 1.4750V regardless of the VCore setting and the savings are somewhat limited. If you disable Turbo-Core you can manage to get even further down. We did 1.1750V in the BIOS. Everest still shows about 1.2000VCore, but that's still impressive when six cores are at work.



As usual our benchmark parcours with our standard benches.







It's quite amazing that the Phenom II X6 still kept the TDP at the same level as any Phenom II X4. Thanks to ASRock we could also play with the new 95W TDP 1055T. Short story: This is the first CPU which can reach efficiency levels of the mainstream Intel Core i5s and i3s. Please note some CPUs can't work with integrated graphics such as i5-750 and i7-975.



Here the plain power-consumption using lamemt and 3DMark.  Please not that even quad-cores are not fully utilized, but the results should give you an overview what to expect when gaming.



System Cost:

We have put together all the prices except PSU, Case and Drives, While the MSI 785GM-E65 is not any more available we changed it to the MSI 785GM-E51 which also supports X6 CPUs, the Intel 1156 CPUs uses an ASRock H55M Pro (a tad more expensive compared to the non-Pro version) and the i7-975 got an MSI X58 Platinum. All systems with 4GB DDR3 memory clocked at 1333MHz regardsless of the X58 triple memory support. Because the X4-620 is not any longer available we changed the CPU to the X4-635 and upped the 620 scores 11% to reflect the increased clock of the 635.



Do we really need six Cores? That depands on what you want to do with your computer. For people into rendering, video encoding more CPU cores won't hurt. For gamers it's just not that important, because most games are limited to three threads. So while gamers may not benefit of more cores they might benefit from the Turbo-Core function which is similar to Intel's Turbo Boost.

The really amazing thing is the quite low power-consuption of the six Cores. There is not much difference in power drain with the X4 CPUs but clearly AMD gives Intel a run for its money. As usual the AMD CPUs are a tad slower clock by clock and due to limitations of mostly not AMD optimized codebase. In the latest FCC ruling against Intel, it come to light that Intel might have slowed the competition on purpose, which is not a nice thing to do. Would we use later software version of the x264 codec AMD would have beaten an Intel i7-975, but as you know to retest every platfrom and CPU takes lots time.

The cheaper 1055T is direct competition for the i5-750/760 CPUs. Nowadays you can get a boxed 1055T for €174,- which is just a tad more expensive then a i5-750. The Black Edition 1090T which is unlocked is available for €252,- which is quite a bargain as an i7-950 costs double.

We were impressed with the new six-cores and if you planning upgrading your system you can't do anything wrong using them. Especially the Phenom II X6 1055T can only be recommended for its excellent price/performance ratio for a high-end CPU.


Last modified on 20 August 2010
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