inanition02 :
That card can't support 3 monitors. Only either Sapphire Flex cards or cards with DisplayPort (one has to be DP or miniDP) can support 3+ monitors. (Has to say "Eyefinity")
Get 2 6750s or 6670s, non-crossfire.
That may be true and PROBABLY IS, however if he doesn't have a VGA compatible monitor there is no point in getting a more expensive card unless it supports three outputs that are non-VGA (i.e. 2xDVI and 1xHDMI). You mention DisplayPort which is fine, but he should look at:
a) TOTAL COST (cards plus DisplayPort adapter if a Displayport monitor)
b) total slots used
c) extra heat by more expensive cards
The AMD link for the HD6450 states up to THREE displays without DisplayPort, however that depends on how the MANUFACTURE implements it. My guess is that only two monitors are being supported by most/all due to the small cost difference to support three.
I guess you'd have to find a review, or the Manual for a specific card to know whether it actually supports two or three cards. Again, if he doesn't have a VGA monitor it doesn't matter.
Maybe he should get a single card and find out.
About VGA:
VGA output is exactly the same as the DVI output except that it passes through a Digital-to-Analog Converter first. It then is used directly by the older CRT (tube) monitors or goes into an Analog-to-Digital chip. The quality difference between VGA and DVI is hard to see.
Why HD6450?
These cards are inexpensive and you can get fanless, single-slot solutions so three cards would only take three slots. For non-gaming use it's pointless to invest in more expensive cards since the processing is usually done on the CPU (that is slowly changing with OpenCL).
For about $100 for three cards (six monitors total), using three slots I'm not sure that there is a better way for his needs.
FANS:
While you can get fanless, 1-slot solutions I strongly recommend case fans. One in the bottom-front, and one at the top-rear. If you need to buy one these are the rough specs:
- 120mm (12cm)
- 4-pin molex (or with adapter)
- non-variable speed
- max 800RPM
- max 18dB noise
(simply install directly to the power supply and leave them running all the time to create an air flow through the PC. If you have a crappy case consider an inexpensive Antec for about $50 which has two pre-installed fans. See NCIX and the Antec site for details.)