I've been tinkering with some random video cards today and I am being reminded of yet another reason that I don't spend much time with ATi hardware before the R300\RV350 era.
I have two 8MB ATi Rage Pro cards that look nearly identical, except one is a "Rage Pro Turbo PCI" with 8MB onboard and the other is a "3D Rage Pro PCI" with 4MB onboard + a matching 4MB expansion and TV outputs. When I ran some games on them I noticed the one with the expansion was HORRIBLY slow. Like, it felt like a first gen S3 Virge, even at 640x480. The other card ran significantly faster. Not great, but far far better than the other card... certainly decent enough for a 2D\3D accelerator from 1997.
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The BIOS chip on the slow one is marked RAGEPR PQFP 41904 107, the faster one is RAGEPR PQFP 41902 106.
I decided to check their clock speeds with PowerStrip and... whelp... I think I found the problem!? According to PowerStrip the faster one is clocked at 75Mhz Core, 100Mhz memory (higher than it seemingly should be, but correct for the 10ns SGRAM). The slow one? 36Mhz Core 48Mhz RAM!! What gives? Why is it clocked SO low??? Even the RAM is massively underclocked, since it also has 10ns SGRAM like the other card.
PowerStrip calls the faster one an Xpert 98, the slower one is an XpertPlay 98 or something like that.
I don't get this since everything I can find online says that the a Rage Pro is a Rage Pro, and any variations were just rebadge attempts by ATi to get people to take another look at their cards after they improved their drivers.
Also, the one with the memory expansion has a label on the back that says "NON-UPGRADEABLE" ... @_@
ATi was just such a baffling company back in those days. They had ~10 years more experience in this industry than most of the other companies that were succeeding in 2D+3D in the late 90s, their hardware was very well built (tantalum caps, nicely built boards, efficient and low heat output), most of their products were entirely first-party... but there was so much of this just inexplicable weirdness from them that just exacerbated their driver woes.
I am going to pop the BIOS chip out of the fast card (the OLDER version as far as I can tell) and drop it into the slow one to see if it "magically" turns it into a useful card with no other drawbacks. I bet it will. I will post back later once I have done this.
EDIT: Forgot to mention, they're using the same installation of the 2474 Rage driver.
EDIT2: Well, I didn't have to swap the BIOS chips. Inexplicably both cards are running fine now after some reboots and swapping cards back and forth. Powerstrip still detects the 4+4MB card with weirdly low clocks, so that appears to be wrong.
I also checked the clocks with SIV and the 4+4MB 3D Rage Pro shows 75Mhz core and 75Mhz memory, which is actually accurate. SIV also says that the 8MB Rage Pro Turbo is 200Mhz core, 100Mhz memory... which is clearly wrong. So, yeah, these cards must just be hard to measure the clock speed on. I haven't looked for an ATi Rage specific overclocking tool yet.
I haven't run any benchmarks to see if either is faster than the other, but I don't think it matters much at this point. They're probably decent cards for games up to 1998 or so.