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AMD Phenom II X4 965 Black Edition |
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Written by Fedja Drndarski
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Sunday, 27 September 2009 |
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Page 2 of 4
Overclocking
Since we have CPU with “old” Deneb C2 core, some spectacular overclocking results are not expected. Our AMD Phenom II X4 965 belongs to Black Edition series so multipliers are unlocked (core and northbridge/L3). With simple change of multiplier in BIOS or using AMD OverDrive or K10-stat tools we can raise CPU frequency in 100MHz steps and 200MHz for northbridge/L3 section.
If we reflect on previous models of Phenom II X4 CPUs we can conclude that overclock margin is raised for 100-150MHz, compared to AMD Phenom II X4 940 CPU . Stable overclock on AMD Phenom II X4 965 was reached at 3.82GHz at very accessible Gigabyte MA770T-UD3P motherboard based on AMD 770 chipset with SB710 southbridge. All this was achieved with memory controller and northbridge operating at 2.8GHz, which is great result. Since this Gigabyte model didn’t have any cooling system present on power section this results are truly remarkable and comparable to those achieved by much pricier AMD 790FX based motherboards.
We should mention that for most benchmarks this motherboard was stable even on 4GHz, but we wouldn’t recommend these settings for 24/7 exploitation. For such scenario, some cooling system should be present on motherboard itself, and some advanced CPU air cooler should be recommended. If you take a look at results you can see how much AMD CPUs have improved over the past year. Overclocking scaling of Deneb cores is much better compared to old Agena core. Integrated northbridge with its 6MB of L3 cache compared to 2MB present on 65nm Agena core, scales performance levels much better with increase of core frequency. Besides, IMC/L3 inside 45nm Deneb core moves frequency limit at 2.7-2.8GHz compared to 2.3GHz on old K10 Agena cores. This means that if you got 13% of overclock for CPU and by doing that you raised frequency of memory controller and L3 cache for 30%, you will get more than 13% performance increase, since all this will result in increased IPC (Instructions per Cycle) that your CPU is capable to support.
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