The Suzuka Opteron is old-tech: 4 cores in a 115W TDP package and 2.2 GT/s HyperTransport; the Opteron 1381 is 2.5-GHz; the Opteron 1385 is 2.7-GHz; the Opteron 1389 is 2.9-GHz. There are/were the Opteron 13KS EE (50W TDP, 2.0-GHz) and the Opteron 13QS HE (71W TDP, 55W ACP, 2.4-GHz). If you're looking to add a new machine to your business, that's not going to be cost-competitive, especially in terms of performance/value, when contrasted against modern platforms.
A bit of shopping will reveal that an Opteron 4200-series server is considerably less expensive than most mainstream Core i5 and Core i7 consumer-grade "solutions." If you're desperate to pinch pennies, the Opteron 4234 (6 Bulldozer cores; "3-speeds": 3.1-,3.3-,3.5-GHz) is typically $175-180 apiece (shipping included) to addresses in the 48 contiguous United States. Pit that against ~$320 for the ubiquitous Core i7-2600K, or ~$300 for the Core i7-2600 (at TigerDirect), each of which has 4 Intel cores and is a "2-speed" CPU: 3.4-, 3.8-GHz), and you see Intel isn't quite the bargain it's made out to be. Even the Core i5-2500 (4 Intel cores; "2-speeds": 3.3-, 3.7-GHz) is $210 at Amazon. All these are 95W TDP. The Opterons are 75W ACP; who knows what is the ACP for the Intels?
I just looked at a couple of 2P Socket C32 boards for a build; I needed a lot more power than what you're looking at, so expect a 1P server board to be significantly less.
The Asus KCMA-D8 board is $289.99 with free shipping (from Newegg; the mail-in $20 rebate lowers the effective price to $269.99) to addresses in the 48 contiguous United States. Together, that's under $450 for the Mobo & CPU for a 1P "entry-level" server using the Opteron 4234 in a 2P board, meaning you can upgrade to 2P (12 Bulldozer cores) performance for just the price of a CPU: Intel can't touch that! And without changing the motherboard, you could upgrade to a pair of Opterons having 8 Bulldozer cores apiece, for a 16-core, single-board machine: from the 4256EE (35W TDP, 32W ACP, "3-speeds": 2.5-,2.8-,3.5-GHz) all the way to the 4284 (95W TDP, 75W ACP, "3-speeds": 3.0-,3.3-,3.7-GHz), it's 8 Bulldozer cores per package.
The Socket AM3 Tyan S8005 motherboard comes in 3 flavors; the S8005WAGM2NR ($253 + S&H, from Atacom; $261.11 from Amazon with free shipping) is sufficiently inexpensive I didn't bother chasing down prices for the other versions. Any decent 1P-only LGA1155 or LGA2011 board is going to be at least equal in cost to the 2P Asus KCMA-D8. That's not a recommendation: it's just to point out that AMD does offer some benefits at the lower end of the performance spectrum.
Okay, technically, you're going to want to add RAM for the second CPU -- but (again, if you're pushing for cheap) the Opteron 4200-series and the Opteron 6200-series CPUs will allow you to use inexpensive, non-ECC, unregistered RAM, and the Opteron 4200-series uses dual-channel memory (same as the consumer-grade Intel CPUs I mentioned). In other words, there is NO cost premium for the upgrade to professional-grade architecture and the Opteron system -- and, once you're in a position to be able to afford the benefits that ECC RAM offers, you can upgrade to that without having to get an entire new motherboard and a ridiculously-expensive Xeon CPU.
If you're stuck on the idea of a 1P-only solution, you might consider the following (presented here in no particular order):
Supermicro H8SCM (~$207 online from various retailers)
Supermicro H8SCM-F ($230, with free shipping, from CompSource)
Tyan S8010GM2NR ($239.99 with free shipping, from Amazon)
Tyan S8010G2NR-LE ($209.99 with free shipping, from Amazon)
Tyan S8010WGM2NR ($339.99 with free shipping, from Amazon; or $339.99 from Newegg with their advice, "Log in to see discounts and use shopping cart.")
The Opterons will give you better power management and better performance, and will present you with options not available to you from consumer-grade equipment like the Phenom X6, or the non-Xeon Intel products.
Note: MSI lists a couple of boards for C32 Opterons (for 1P applications, the MS-96D7; for 2P applications, the MS-91F7), but I can't find a retail source for these anywhere on the web. Tyan does custom runs for some of its boards, and it is possible that you'd have to go to MSI to get one of their boards mentioned here. I haven't checked with other manufacturers.
Edited: 04/13/2012 at 01:04 PM by Havaneiss Dei