It'd be easier to recommend what you should be looking to buy at a particular budget. You could then take that and look at some of the benchmarks. What are you looking to spend on the machine?
I can tell you that in the desktop areana (I have no idea on the server CPU side), your best bets (in price order) to achieve it are the i7-2600K, i7-980X, and i7-990X. It's entirely possible that the X6 1090T, i5-2500K or i7-950 could achieve what you're trying to do as well, but I don't know much about exactly what kind of task you're looking to do. Here's
Tom's latest 3DS Max benchmark, which I'll be using as a rough benchmark for the 1200x900 resolution. The i7-950 and i5-2500K isn't on it, but they'd both be a touch behind the i7-960, with the i5-2500K being a little faster than the 950.
For the CPUs, the i7-980X and i7-990X run around $1,000 (or higher), with LGA1366 boards costing $200 and up. The i7-950 is $280, with the same LGA1366 boards. The i5-2500K is $230, while the i7-2600K is $330. They use LGA1155 boards, which run $150 (ASRock P67 Extreme4) to $190 (Asus P8P67 Pro). The X6 1090T is $200, with AM3 boards as cheap as $75-90.
Of course, you'd want to pair those with as much RAM as you could afford. That'd be around $200 for 16 GB of DDR3 1600 CAS Latency 9 (two 2x4 GB kits for $100 apiece) if you get the X6, i5-2500K or i7-2600K. For the other i7s, it'd be 24 GB of similarly speced sticks (two 3x4 GB kits for about $165 a piece) for around $30. You'd likely also want a fairly meaty nVidia Quaddro GPU, which typically start around $200-300, and can run as high as you need them to. I'd probably say you'd want one that's closer to $1,000 than the $300, but again, I'm not that knowledgable about those models. For purposes of pricing, I'll say it's a $1,000 one.
So for the major components, you'd be looking at a range like this, which is in rough price and performance order:
X6 1090T: $1,475-1,500
i5-2500K: $1,580-1,600 i7-950: $1,810-$1,850
i7-2600K $1,710-1,750
i7-980X/i7-990X: $2,530-$2,570
You'll also need all the other components (PSU, HDD, case, optical drives), which will be around $250-300. Add $100 for Windows 7 if you need it. So all told, you could get in the door with around $1,875 (with OS). I'd really like to fit at least the i7-2600K in there, so it'd be better to look around the $2,100 mark.
It's entirely possible you could get by on less, especially in with the GPU. I'd be surprised if you got something with similar performance for cheaper on the server side, at least until you start talking about the i7-980X or i7-990X.
EDIT: For comparision purposes, the benchmark I referred to is only using 8 GB of RAM (i5-2500K, i7-2600K and X6 1090T) or 12 GB (i7-9xxs). If you throw more RAM in there, it'll speed up. In addtion, it was using the GTX 580 ($500ish), which would surely be eclipsed by a $500 workstation Quaddro card. If you need more details on what is in the machine they used to benchmark or what settings they used, it's on the third page of that article. Given what they did with a $500 GPU, you could probably knock $500 off those estimates.
EDIT #2: If that benchmark is spot on for what you're looking for, you could probably even drop down to the X4 955, possibly lower. That'd shave anouther $60+ off the budget. According to
Tom's 3DS Max CPU chart, even the lowly X4 640 ($100) beats the 5 minute (300 seconds) mark.