Overclocking Conroe on RD600
As far as overclocking goes, this has to be one of the biggest surprises of the ATI RD600 chipset. There have been rumors floating around the Web about this but until now all these rumors were from ATI or one of their partners. We are here to tell you, the rumors are true.
Intel has always been able to offer the best overclocking support for their processors with the 975X and previous chips but it would seem Intel is in for a shock - along with the rest of us. We removed the X6800 Conroe processor from the socket and installed a more overclocker-friendly CPU, E6300 Core 2 Duo and that's where the fun started.
We dropped the multiplier back to 6 and set the FSB to 440MHz and the system actually booted - that is 1.86GHz up to 2.64GHz - on a reference motherboard, with stock standard air cooling. While the system posted and loaded into Windows, it would hard lock as soon as you tried doing anything stressful. It even managed to run quite a few seconds of 3DMark05 at 2.64GHz before overheating occurred and the processor began to throttle itself back to reduce temperatures.
We played around with the FSB settings for a while and discovered that 420MHz x 6 (2.52GHz) was very stable, with the processor voltage at default. This resulted in an overclock of 660MHz and it does help turn the cheapest Core 2 Duo processor into a much more respectable performing CPU up there with the likes of the much more expensive E6700 Core 2 Duo. This information is based on the benchmark numbers in an article recently published by Anand over at AnandTech.
That effectively means you are buying an E6300 CPU priced around $183 USD which in gaming benchmarks is almost as fast as the E6700 CPU priced at around $530 USD - you do the math - it is definitely tremendous value through overclocking. Spend some extra dollars on a better cooling setup and you'll likely be able to push the processor clock speed even further. The consensus was we were being limited by our cooling setup with the temperatures rising too high.
ATI designed the RD600 to handle very high memory frequencies with the CPU and memory running in an optimal performing 1:1 ratio. Imagine when retail motherboards come out, which should be able to run stable at around 450MHz (according to our friends in the know), and you've got a pretty kick ass gaming platform. Your $183 USD CPU is rocking along at around 2.7GHz and your more expensive memory running at around PC8500 speeds in 1:1 ration with tight timings. That is sure to make any overclocker grin along with the sales people at ATI who are looking very much like they have a real hardcore enthusiast chipset platform just ready and waiting to enter the market.
We also had access to a reference nForce 5 Intel Edition motherboard based on the C19 revision "C" chipset. Since this chipset is now quite old and operates at a hotter temperature, overclocking is quite a long way behind RD600. The maximum stable FSB under the same conditions as the E6300 was 320MHz. nVidia will release their response to RD600, C55, in Q1 or Q2 next year but at this stage we have no information on the overclocking ability of this upcoming chipset.