Linux – Does any current workstation class graphics card support four monitors with RHEL 5

I currently use a RHEL 5 workstation with a pair of Nvidia Quadro graphics cards, feeding four WUXGA (1920×1200) monitors. Unfortunately, using Xinerama to get a single X desktop means loosing much of the hardware acceleration these cards could provide.

Another machine here with quad monitors has two X desktops, with two monitors on each. Using two X desktops means that all monitors are hardware accelerated, but it also means that you can't drag windows between monitors that are on different graphics cards.

We did hope that using a dual GPU card like the Nvidia Quadro Nvs 450 would solve our problem, but it turns out that as far as X is concerned, two GPU's on one card is treated the same as having two graphics cards, triggering the same problem.

I believe that Eye-finity on the AMD FirePro workstation graphics cards would allow us to use a single four monitor X display, but we are almost exclusively an Nvidia shop, so I'm reticent to suggest this. Also, while I can see a number of people claiming to have triple monitor set-up working with RHEL 5, I can't find anyone claiming to have quad monitor setup working and AMD technical support are being less than helpful.

I was assured by Matrox technical support that their M9140 and M9148 cards would be ideal, and initial testing confirmed that the M9148 cards did work, but in production we found that their performance was inadequate and all but one workstation equipped with these boards had to be reverted to their old Nvidia cards.

So,

• Can anyone confirm whether Eye-finity supports 4 monitors on a single X display without Xinerama on RHEL 5?
• Alternatively, can anyone suggest any alternatives which might allow a RHEL 5 workstation to support 4 monitors with hardware OpenGL acceleration on all screens?

Incidentally I know about Matrox DualHead to Go,but have dismissed that as an option since we would end up with two 3840×1200 or 1920×2400 virtual monitors, where maximising a window would maximise over two monitors – we would prefer maximised windows to be constrained to the monitor they were on.