I would say, think about adding more ram first......

for $500, get a Matrox or ATi, don't think about Nvida

但GeForce既色準同sharpness不及ATi或Matrox...

agree with rtao, dont buy nVidia.

補充少少:
市場上已有 Radeon 9200 64MB DDR RAM，
都是$4xx 尾...
不過我未試過，吾知性能同熱量是怎樣??

Matrox就是出Gxxx同Parhelia那家了, 色準, 2D畫面非常sharp, 她的dual head比GeForce好好多...

The speed of filter in Photoshop is NOTHING about the display card ability!!
Some filter, like radial blur is said to be super slow and need huge among of CPU/FPU task, the faster your CPU is, the faster your filter is.
If I were your friends, I would use the $500 to buy a new 1.8G Althon.
Also, you may need to upgrade your RAM to 512 or more. If you use Win2K or WinXP, the windows already eaten a large among of system memory while start. If you have several hundred of fonts and plenty of memory resident programs, the total useable system memory may drop to less than 50MB!
By the way, have you changed the default setting of Photoshop in the memory menu??

.ps nVidia is not that worse any others in color accuracy. But the D/A output is not that
sharp when compare to ATI and Matrox. If you search for a low price and good display card, ATI 9000(pro) is a good choice. It has dual 10bit D/A and medium 3D speed.

re:raymondchan
你個friend有冇係photoshop個Preferences之類把Ram盡量分配比photoshop用，否則它只分配一部份Ram比photoshop用！？
我記得PC好似係Photoshop Preferences set，我用開Mac機係其他地方set。

多謝各位的意見.
我懂得怎樣set Photoshop的Ram的分配,我會幫我的朋友set的.
關於超人的意見,我覺得有道理,不過我還想進一步了解Display Card在整部電腦擔當甚麼角色,而Display Card的Ram又有甚麼用?
如果買Ram,就當然會買512M SDRAM.
部電腦用Sony的Trinitron CRT,都算幾好的啦.我估計不用onboard的Display,而加一張AGP的色會好好多.
還有一件事,我覺得我張用了好幾年的TNT2 16M都係時候換一換了.

很吸引的話題！
我也正想換張好顯示卡做圖片用，但從來不會打機的！價格合理的話，有什麼推薦？最好注明在哪裡買得到。

For photoshop you need large (and fast) hard disk and many ram if your image is very large or you open many images at the same time with many layers.  Harddisk is used as virtual ram and temporary storage.

If you need to have faster filter, you need very fast CPU or dual CPU (dual cpu has better performance, as photoshop has capabililty to use dual cpu when rendering).

Display card speeds up the redraw speed in 2D performance in photoshop, so you don't have to wait so long between redraw of images e.g. when enlarge, redraw after applying filter.