Investigations into Athlon X2 Overclocking

RAM Ratios

We mentioned before that additional RAM ratios would be helpful, and higher end motherboards like the DFI LanParty series often provide them. The Infinity board is limited to DDR400, DDR333, DDR300, DDR266, and DDR200 – at least with the current BIOS. In reality, these are not exact speeds but rather the maximum speed at which the RAM will run with the CPU at stock speed. RAM speed on AMD K8 systems is derived from the CPU speed. With our X2 3800+, “DDR400” results in a CPU/10 RAM divider. 2000/10 = 200 MHz. The 10X multiplier actually makes for very nice RAM speeds, as CPU/12 = 166.7 MHz, CPU/15 = 133.3 MHz, and CPU/20 = 100 MHz. The DDR300 setting is the only one that’s off, as 2000/14 = 143 MHz.

With other motherboards, you may get several additional memory ratios, including those above DDR-400. This provides additional options for reaching maximum performance. In the end, the memory ratios come down to one point. All things being equal (i.e. with identical timings), higher bandwidth will be faster. It may not be a lot faster, but it could be a difference of several percent.

Was that a third strike against the Infinity motherboard? Though we would still say it packs a lot into a $90 board, we would recommend that serious enthusiasts spend a bit more money. The LanParty Ultra-D from DFI is only $20 more, and it has quite a few advantages over the Infinity that will be appreciated by more ambitious overclockers. The Ultra-D is basically the same as the SLI-D, only without official SLI support. Motherboards based on ATI's latest chipset also show promise – check out our motherboard reviews for more details on specific motherboards.

We could have tried several different motherboards to see if we could achieve better results, but this isn’t a motherboard or RAM article, even though it has aspects of both types of reviews. This is merely intended as an aid in showing people what can be achieved using the options available with various RAM types on one motherboard with one CPU. In other words, don’t read too much into the memory results. Use them as a guideline for optimizing your own system performance.