Computer question

[Devin Johnston]

I'm at the point where it's almost time to get a few new machines for the render farm. I'll be replacing 5 older render boxes and I've been looking at different configurations and I've gotten some surprising results.

All of these computers are dual core dual processor AMD Opterons with 4 gigs of ram, basic hard drive and video card, 1 Gigabit network card and CD-ROM drive:

 

To purchase 5 new render boxes it will cost $13,922

To purchase 5 new workstations it will cost $13,642

 

To purchase 1- 8 processor workstation it costs $10,074 and 1 dual processor workstation that costs $2,872. The total cost for those two machines is $12,860.26 after discounts are applied.

 

It's obvious that the combo unit of the two different machines is cheaper than either the workstations or the render boxes. My question is what if any performance difference would their be between the 5 workstations and the combo units since between them the workstations have 20 Gigs of ram and the combo unit only has 4. Is there any advantage or disadvantage in going with a combo system like this?