I have a Gigabyte Radeon HD 4550 128mb hypermemory and a Dell inspiron 530s PC.
Ive currently overclocked my Graphics card to a core speed of 730MHz and a Memory clock of 950MHz using ATI tray tools, but when i go higher than that the card shutsdown in less than a second!, i thought of this as a temperature issue but the card runs at 70 degrees at full load. From my own knowledge i suspect this is because im trying to clock my card faster than my PCI-E bus and cant outrun my RAM which is, 2GB DDR2 SDRAM 667MHz.
If i can get around this problem will i be able to clock my card even higher??