Well for the second time I'm having a great time with my matrox...

I sent my 7900Gs to msi when it didn't work anymore, and -after two month- they sent it back and at first it was working and relativly stable (one to two bluescreens a week). But now it's just as before, same symptoms, Pc crashing for random, with grafic errors, sometimes I have to wait an hour, before it's able to start correctly after such crashes...

I have no sense for waiting another two months so I'll take my "chance" and upgrade my grafics.

I have 130€ max. 150€.

I have focused on two grafic chips:

1: Geforce 9800GTX+

2: Radeon HD4850

The question is:
Which of this one do you recommend and which publisher?
There are good prices on Zotac and Gigabyte (and MSI but I don't think that I'll buy Msi in the next time) for the 9800GTX+
and HIS or Sapphire for the HD4850.

Another point is: Does it make sense to buy these cards with 1024mb instead of 512? (the price is all in all comparable at least for the radeon)

Who has got one of these cards and can give me some advice (I'm expecially interested in temperature as my cooling system isn't best)?

Or does anyone have a better hint for a chipset?