I posted this same question on the Autodesk hardware forum and got some interesting information.
"Tough call. I like the X2 systems a lot, based on a couple of reasons.
To get an idea of the performance metrics of each CPU, we can base this
using the 3ds max 7.0 scores as reported by GamePC:
Benchmark scores:
1 x X2 4200: 161
2 x Opteron 275: 144
(lower times are better)
Given this, we can see that a dual Opteron 275 system kinda spanks the single X2 in rendering tasks, being around 10% faster. No surprise, as you are pitting 4
CPUs of computing horsepower against 2, and 3ds max/VIZ is one of the few apps that can actually use these extra CPUs. But is that 10% enough to make your rendering farm better? Especially since there seems to be a point of diminshing returns after 2 CPUs in max.
At the hardware level, the Opterons give you 3 boxes to deal with instead of 5. That means a savings by not having to pay for 2 extra systems, not to mention lower shipping costs. This savings is somewhat offset by the added cost of each dual Opteron system, however. We can probably call the price a draw. Network connections are essentially free and not part of the cost issue.
In terms of power consumption, GamePC’s benchmarks show the Opteron systems consume 282 Watts under full load, while the X2 only consumes 181 Watts. A 3-system Opteron farm is 846 Watts, while the 5-system X2 farm is 905 Watts. Thus, the Opteron farm will cost about 7% less to operate, which is also about a wash.
But to make a final determination we must compare IF the additional 2 X2
systems make your distributed rendering system more efficient and make up for the slower rendering times against fewer Opterons.
Let’s assume a single X2 will render a scene in 10 hours. Given the benchmarks above, one dual-CPU Opteron system will render the same scene based on the equation
[(10 / 161) = (x / 144)]
Solving for X = 8.94 hours for the Opteron system.
Assuming the additional systems in the rendering farm divide a task equally, 5 X2 systems would render the scene in only 2 hours. However, 3 Opteron system would render the scene in 8.94 / 3 = 2.98 hours. 4 Opteron systems would finish
in 2.23 hours. It would take 5 Opteron systems to see any time savings!
Conclusions:
The marginally faster rendering times provided by the Opteron do not scale against using more but slower X2 systems in this scenario. At this level it takes the same number of Opterons to beat the same number of X2 systems.
Go with the 5 X2 systems.
Matt
mstachoni@comcast.net
mstachoni@bhhtait.com"
You can read the whole thread at:
http://discussion.autodesk.com/thread.jspa?messageID=5069212%26#5069212