Stability

At stock settings, the K7V is a muster in stability. There were no lock-ups at all. Despite the warnings in the manual not to run SDRAM simultaneously with VCM, the K7V is the first board we found to tolerate coexistence of the two species without any hickups. In terms of performance, the results were statistically indistinguishable from those obtained running either HSDRAM or VCM alone. However, there was more variability in the benchmark results.

Unfortunately, the situation changed immediately when we initially attempted to overclock the system. The problems started with trying to change the BIOS parameters upon which the system refused to reboot.

The most sensitive issue appeared to be the memory frequency, that is, the 4:3 setting could only be run at external CPU speed up to 105 MHz. Above that, the system could be tricked into accepting the setting but was not stable. This finding was reproduced on either Athlon 600 and 800 MHz version using EMS HSDRAM or any other SDRAM.

The culprit in this case turned out to be the DRAM read latch delay which, by default is set to 0.5 ns. By increasing the value to 1 or 2 ns, depending on the bus speed, the system became absolutely stable and had no problems either saving the settings into the BIOS / restarting.

In case NEC VCM (rated at 143 MHz) was used, the situation was worse in that there was simply no way to even boot using the 4:3 setting at any but the 100 MHz default bus speed (DRAM read latch time = 0.5ns). A complete analysis of the DRAM read latch time on VCM would exceed the frame of this review but the pattern is similar to what was said above for SDRAM

Other BIOS parameters that turned out tricky comprised the Vre, that is, as long as it was set to Auto, there were no real problems, however, changing to manual and selecting any voltage between 1.6 and 1.75 V resulted in failure to boot using the 800 MHz Athlon. The 600 MHz Athlon, on the other hand booted well with the manual voltage selection, however, for some reason, lacked stability in some applications. After running the system for about one week straight, the glitch concerning the manual voltage settings mysteriously disappeared. We have no further explanation for this.

The highest we were able to push the board to a full load of Win98 was the 112 MHz bus using the 600 MHz Athlon (672 MHz), the 800 MHz CPU made it safely through the 110 MHz setting. We were able to boot at 115 MHz bus speed but Windows Protection Errors terminated further attempts to get performance data.

To conclude, there is a substantial potential for overclocking as long as the correct parameters are selected in the BIOS.

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