jfall,
I am certain you will see a performance improvement, but cannot quantify it. However, what I can tell you is that the K7S5A tends to be somewhat "quirky". I say this as an owner who installed the mobo myself (first attempt at this) and have had NEXT TO NO PROBLEMS. However, I am fairly active on the K7S5A Motherboard Forum (
http://pub65.ezboard.com/bk7s5amotherboardforum), and note that there are some significant problems others are having with this board. I consider myself very lucky, as it appears you may get a "good" board or a "not-so-good" board. I have not been able to correlate board revisions to potential problems, but can tell you that I have the Rev 3.1 board with onboard LAN, purchased and installed in May 2002.
A suggestion: If you're shooting for the K7S5A mobo, you might want to consider the K7S6A with the SiS 745 chipset instead of the K7S5A with the SiS 735 chipset. You can read about this mobo at
http://www.amdmb.com/article-display.php?ArticleID=159&PageID=2 and at
http://www.ocworkbench.com/hardware/elite/k7s6a/k7s6ap1.htm. Having said that, I will tell you that I am very pleased with the SiS 735 chipset, and am assuming that the SiS 745 with its upgraded features will perform equally well.
I purchased the K7S5A for two primary reasons:
1) I wanted SDRAM support with the ability to upgrade to DDR. The K7S5A provides this option by supporting both types of memory, though you can only run one type at a time. The K7S6A does not support SDRAM, so if you want that support, you must go with the K7S5A.
2) I was sick of all the patches required by the VIA chipsets. I was pleased that I needed only install an AGP driver and, for Windows XP, a USB registry patch (usbdetect.exe). Both operations were painless. Following installation of the mobo, Athlon XP1800+ and Win XP Home Edition OS (clean install, not upgrade, using FAT32 partitioning), I experienced a successful bootup the very first time.
Now, to the problems. I myself have been subjected to one of these, which is loss of BIOS settings. I have only experienced this two or three times since installation in May; at least one of these followed connection of the power cord. At that time, I was swapping the power cord back and forth from my old to my new system. After the BIOS glitch, I ceased doing this, now using two separate power cords instead; I have not experienced the problem since (for months). Some people on the forum complain about this problem occurring as often as several times a week. The fix may be as simple as rotating the CMOS battery in its housing to provide better contact. There are other potential solutions to this problem as well. There is also a (more radical, but still simple if you know how to solder a mobo) 470-ohm resistor mod that is supposed to help rectify this and perhaps another problem. (My memory fails me here.)
The next major problem -- the one most widely reported -- is inability to run dual sticks of SDRAM without system instability, sometimes severe. Well, what can I say? I run two matched 512 Mb sticks of Crucial PC-133 SDRAM. I do not overclock. I have had ABSOLUTELY NO memory problems. I suspect that either this mobo does not like certain brands of memory, people are using mismatched sticks of memory, or power supply inadequacies are in play. While some people report that converting to DDR eliminates the problem, others complain of the same issue with DDR, making clarification of the issue even more elusive.
Finally, there is a fairly common complaint of instability that has been traced to overheating or, occasionally, UNDERHEATING of the SiS735 chipset. There is a heatsink mod that fixes this problem.
The only crashes (actually, lockups) I have EVER had with this system are related to Internet Explorer 6. Having many [5 or more] browser windows open, although minimized, at once and trying to simultaneously update two browser windows at once will lock up Win XP. I have duplicated this problem and know that it is not a hardware issue.
So, I've scared you, right? Let me suggest the following. Start by browsing the K7S5A Motherboard Forum. See what you think of the posts there. Be certain your power supply is sufficient and stable. If you decide to go with the K7S5A, be sure to buy from a reputable company, get at least a one-year warranty, insure that the company you purchase from does not have a restocking fee or some other ripoff policy, and be prepared to return the mobo for a replacement if it does not meet your expectations. It might also be a good idea to have an alternate mobo selected if you continue to have problems.
Scared you more? Let me reiterate that I CONSIDER MY SYSTEM WITH THIS BOARD TO BE EXTREMELY STABLE; I like it a lot, consider it to be extremely fast (though I am not a hard-core gamer), and hope to continue using it for many years to come. My own ECS experience has been very positive. Therefore, I cannot help but give the K7S5A a thumbs up!
I have subscribed to this thread, so if you wish to ask further questions, I will try to answer them.
Best of luck!
Ken