Multihead graphics card help

Hi.

For my CAD machine, I am currently running a Foxconn Black Ops motherboard, running a Core 2 quad processor with three 512MB Radeon HD3850 cards, driving a six head 24 inch dell monitor setup under XP. I have recently been having some problems with the system, which point to either a driver issue or possibly a faulty graphics card.

For some time I have been wanting to update the machine to a faster one, and soon will be putting in a Z77 based motherboard with a Core i7 Quadcore Ivybridge processor running windows 7.

The problem is that i also want to update the graphics cards to something newer and hopefully quieter. The machine currently contains about 7 fans, and is fairly noisy. What I really want is passively cooled dual or triple-head graphics cards.

Some time ago I experimented with a pair of allegedly triple-head HD6450 cards I acquired, but to my annoyance found they were unsuitable for a couple of reasons. One was that even though they had three video outputs (two DVI and one HDMI), only two of these could be used at once, although the seller swore blind that all three could be run at the same time.

The more serious problem was that they were slow. By this, I mean SLOW! Redraw speed in the various CAD packages was almost funny it was so glacial. It took about 2 seconds every time the screen refreshed whenever I panned the view, which rendered (Hah!) the whole exercise a complete waste of time. The much older HD3850 cards perform the same redraw instantly.

I am rather out of touch with the current state of graphics cards, not having done any serious gaming for three or four years. Can anyone recommend a decent card with the following features:

Preferably passively cooled.
MUST be single slot.
At least as fast as an old Radeon HD3850.
At least dual head, triple head would be nice.
Ideally less than £80 UK.

Although I have used ATI cards for years I am not absolutely wedded to them, I would consider nvidia ones if they met the requirements.

Any suggestions?

pca