Since your motherboard supports both L1 and L2 WB, enabling them would give you extra performance. However, mind the cacheable limit. I can't say for all the chip sets, but sis 496/497 can has these limits:

Anything over the said limits will go uncached, which will result in a serious performance drop if you are using Windows.

I have 16mb RAM and 256kb cache RAM so I should be good to go ahead and set L1 and L2 to WB? Just double checking what i'm seeing on that chart.

Chaniyth wrote:

I have 16mb RAM and 256kb cache RAM so I should be good to go ahead and set L1 and L2 to WB? Just double checking what i'm seeing on that chart.

Yes, you'll be fine whatever chip set you have. Unless there are some compatibility issues 😀

RacoonRider wrote:

Chaniyth wrote:

I have 16mb RAM and 256kb cache RAM so I should be good to go ahead and set L1 and L2 to WB? Just double checking what i'm seeing on that chart.

Yes, you'll be fine whatever chip set you have. Unless there are some compatibility issues 😀

Thanks, I guess i'll run a "before" and "after" DOOM benchmark and see what the difference is.

Definitely turn writeback on the processor on. Honestly, it is hardly worth using writeback on the external cache considering you lose cachable RAM. It doesn't gain that much performance.

On mine, I don't seem to gain any performance by running 32MB and WB compared to 64MB and WT, not even in benchmarks. Although, I haven't tried it with any Windows based benchmarks, only DOS ones. The Intel DX4 is extremely fast compared to my Cyrix DX4 though, which only has 8kB WT cache, compared to 16kB WB, but I expect the cache size and superior FPU are the most important reasons for that.

First assumption, you'd expect WB on both to be best, but there could be cases where one of them writethrough is better -if the pattern of writes and cache line replacements really goes against it.

just remember some scsi vlb cards have a bug in which it can corrupt data when using WB cache

I am inclined to think some motherboards are reluctant to switch WB on. My FIC 486-VIP-PIO simply REFUSES to enable write back regardless of jumpers or BIOS settings. I managed to turn it on with an AMD chip by setting P24D as the CPU type, but it was not stable on that board.

Every other board I have is stable with it enabled though.

I don't know about the whole Write Back being slower in certain cases argument, but it makes sense. There are times when you have less RAM (like 16MB or under) where having 128KB instead of 256K will yield a significant improvement. Overall, cache is a bit quirky and it makes me glad that they integrate it these days, one less thing to worry about - or I don't know what I'm missing out on, whichever, ignorance is bliss.