Asus A8R32-MVP Deluxe: First ATI RD580

Overclocking: Asus A8R32-MVP

Asus A8R-MVP Overclocking Testbed
Processor:	Athlon 64 4000+ (2.4GHz, 1MB Cache)
CPU Voltage:	1.425V (default 1.35V)
Cooling:	Thermaltake Silent Boost K8 Heatsink/Fan
Power Supply:	OCZ Power Stream 520W
Memory:	OCZ PC4800* Platinum (Samsung TCCD Memory Chips) *The current equivalent OCZ memory to OCZ PC3200 Platinum Rev. 2
Hard Drive:	Hitachi 250GB 7200RPM SATA2 8MB Cache
Maximum OC: (Standard Ratio)	246x12 (5x HT, 2.5-3-3-7) 2952MHz (+23%)
Maximum FSB: (Lower Ratio)	322 x 9 (4x HT, 1T, 3-3-4-7) (2898MHz, 2 DIMMs in DC mode) (+61% Bus Overclock)

One of the most interesting new features in overclocking the RD580 is that the chipset is designed for high-speed operation. In most cases, current NVIDIA and ATI chipsets need to have Hyper Transport frequency adjusted to 3X around a 260 to 270 Clock frequency to keep HT speed at or below 1000-1100. The RD580 chipset was designed for higher HT speed. We consistently found that the board could easily handle HT speeds in the 1450 to 1550 range. For most overclocking this means, for the first time, that it is not necessary to even adjust the 5X HT setting for most overclocks. It was only where we were exceeding around 1500 (300 Clock Frequency) that we had to drop the HT one notch to 4X. Overclockers should be very happy with this new feature of the RD580 chipset.

One word of caution: it appears that the RD580 chipset will not reset an HTT strap or ratio unless you first power down. We had seen this in other testing of the RD580 and it is also a reality on the Asus A8R32-MVP. For instance, if you try to set the ratio to 4X (from 5X), the board will not implement the ratio change until you have powered down the system. Thankfully, this will rarely be necessary with the high-speed HTT capabilities of the RD580, but please keep this in mind when adjusting HTT ratios.

The Asus A8R32-MVP required no special approaches to achieve high overclocks. There is no longer the need to inch your way up on overclocks. High overclocks could be set directly, and as long as the settings were workable, it is possible to boot directly into Windows XP at the higher overclocks. However, there were many times when we set reasonable overclocks and the board failed to boot the first time. In this case, power down the board and restart, and your settings will likely work. Similarly, a bad overclock almost always requires that you turn off the power and restart for recovery. Fortunately, the Asus normally recovers, but often you will need to power off first with overly aggressive OC settings.

The 1T command Rate, which was an issue on the A8R-MVP, is definitely working as you would expect on the A8R32-MVP. We confirmed with memtest86 on boot and Systool in Windows that we were setting and maintaining a 1T Command Rate in high overclocks. We did find that Asus is using a very clever tool to protect the board when settings outside the board's capabilities are detected. If we set values (Ratio and Clock Speed) that would result in an HTT higher than the board's capability of about 1500, the board would read 1T Command Rate in memtest86 (prior to Windows boot) and then change to 2T in Windows. Apparently, Asus is lowering the Command Rate to allow a boot under impossible circumstances - after the BIOS initialization. This was never a problem if you kept the resultant HTT within the board's very wide capabilities, but you should definitely find out where HTT fails to effectively overclock the A8R32-MVP.

Asus has also introduced a very unique and effective new means of dynamically adjusting memory timings for the widest possible compatibility. Asus has developed a means of dynamically controlling memory clock skew to achieve better memory compatibility and better overclocks. The best way to illustrate this feature is with a diagram.

By dynamicly extending setup time, Asus claims the overclocking ability of the A8R32-MVP Deluxe is significantly enhanced. Another important effect is improved memory compatability with Auto Clock Skew. Asus also uses dynamic clock skewing on the nVidia-based dual x16 A8N32-SLI. If you own that board, you should download the latest BIOS to make sure you are getting the most up-to-date version of the dynamic clock-skewing feature.

The Asus A8R32-MVP does appear very flexible in handling different memories at default settings, and the overclocking performance at 1T is outstanding. These are certainly indications that Dynamic Clock Skewing is working as claimed. However, some overclocking purists will not be happy with any scheme that second guesses their overclocking settings. For maximum manual control Asus has included BIOS switches for turning off the auto memory clock skew.

You can then manually adjust the memory clock skew for each bank of memory with the broadest range of memory clock skew timing adjustments that you will likely see on any production board.

Those who don't understand overclocking or who don't want to bother will find automatic overclocking options in the Asus BIOS. This allows you to set an overclock and have the board adjust the related settings. These work well for moderate overclocking, but they will not allow the extreme results achieved manually on the Asus A8R32-MVP.