carnonated :
but seeing as $20 is only $20 i think i should buy a 4870. that way in the future when/if i do decide to upgrade my display and CPU/MB i will have the card to go with it? and what is scaling?
also does every MB fir into every computer or do i need a certain kind?
Most cases are built to ATX standards, Dell's may not be.
If you realyl care that little about your money spend it how you want.
Scaling refers to how much increase in performance you get out of increasesing the power of a component. For example, if you add a second GPU for crossfire you are effectively doubling the power (at least the cost

) but the performance you get out of it will not be double (it will be somewhere between 60 and 90% usually).
In our case, I am refering to scaling in the sence of increase of power between the 4870 and lesser cards. At the resolution yuo are playing at, teh scalign between a 4670 and a 4870 may be as low as 10%, yet the price difference may be greater than 100%. That would be very poor scaling. It is froma bottleneck due to teh CPU and resolution you play at.
That resolution can be maxed out by any GPU, the performance almost entirely dictated by the CPU if you have any sort ofmodern GPU.
You can always keep the GPU till you upgrade teh rest of the computer but I am tellign you that there is no point in upgrading until you get a new display. The cash you spend now on a GPU woudlbe almost entirely wasted until you get a larger monitor. But it is your money. Nothing more powerful than a $60 4670 would be worth it because of the poor scaling you are introducing. That is to say that the cost would scale MUCH faster than your performance.