The Radeon 9800 cards are often dead due to them having a shim which prevents adequate contact with the GPU die. Especially with the age causing the TIM to dry out, many of these cards cooked themselves to death.
This is assuming your VGA card has a cooked die though. Still it having dead RAM wouldn't change much from a practical viewpoint as either would probably mean the card is dead. You could try baking it but for now please wait till we get some more answers in here (though I wouldn't get high expectations).

The Radeon 9800 cards are often dead due to them having a shim which prevents adequate contact with the GPU die.

Radeon 9800 coolers had small bump to adress this issue.

You also usually find thermal wax as the thermal interface material with these cards, which is a good gap filler. Otherwise called phase change TIM. It liquifies when heated and it stays in place. Paste won't work properly.

The big R3x0 boards like 9500/9700/9800 seemed to suffer a frequent failure of some component though and this artifacting is the result.

My personal theory - crappy Samsung BGA chips are mostly to blame.

Yeah, probably bad memory, I've seen it a lot, especially on early versions of that card.

Regarding the shim issue, it's interesting to notice that later 9800 Pros do not seem to have that problem. I have a Dell-branded R9800 Pro that has a 2008 (!) date code and the shim on that one doesn't prevent contact with a flat cooler, in fact the stock cooler that came with the card is flat.

The VRAM is indeed from Samsung. I took the cooler off and put another one on and now I'm not getting any output anymore. Oh well seems it was a lost cause anyway.. .