First post, by Blavius
I recently got a new desktop to play around with, an IBM PS/Valuepoint 425SX/S. On paper this 25MHz 486SX isn't very interesting, but it has an 'overdrive' socket and a socketed crystal, which IBM itself says you can replace with a 33MHz one if you need, and I've seen posts of people running it stably at 40MHz. So, lots of potential!
The system has onboard VLB graphics, a S3 86C805 with 1MB. It also has a free VLB slot. I am currently running the system with a DX2 at 66MHz.
I found a guy that was selling a Miro Crystal 20SD VLB, with a S3 86C864-P with 2MB - seemingly quite a good VLB card, and a step up from the not so well seen 805. Unfortunately, the card turned out to be bought by someone else.
What he did offer me instead was a Miro Crystal 10SD VLB, which has a S3 86C805-P with 2MB. So, same chip as I already have on board, but twice the ram and possibly different ramdac etc. I'm confused what to do. I have some questions:
1. Will this card be faster than my onboard solution, even though it has the same chip?
This benchmark shows a 'Vidspeed' score of 16701 for a PCI Crystal 10SD, which is stated to be faster then the VLB (but not by how much). This place however has results for the VLB, which for the same 16bit write scores only 7440 - running at 42MHz. I tried to run "Vidspeed L" on my system and get 20004. So hmm, am I testing my system wrong? What does your gut feeling say, is there any chance this card makes a difference to my onboard?
2. Does it make sense to upgrade to a better VLB card anyway?
I ran some benchmarks on my system. The doom score of 26 fps seems reasonable for a system where the vga is not the bottleneck. Now, let's assume my onboard 805 is similar to the Crystal 10SD (which I am not certain of!). In this benchmark, the doom score this card can achieve on a Pentium 100 is about equal to that what you would get with a Pentium 90 with a very fast PCI card. Then you could reason that only with a system beyond a Pentium 90 you would see any benefit from a faster card (such as the Crystal 20SD). If I eek everything I can from my system with a AM5x86 at 160MHz, its integer performance could almost match a Pentium 100 - so is there even a point in getting anything faster than a 805 in a 486?