How to Choose a Chipset from NVidia (780a SLI) or AMD (790X, 790FX) for the Phenom CPU Family

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By AMD: 790X and 790FX

With its priciest CPU’s at just over $200, and an upcoming series of changes to AMD CPU’s largely capping the upgrade path of the current chipsets, one might wonder if motherboards starting at $150 really make sense. AMD seems to think so, and in fact doesn’t intend users to pair their top processors (those that suck 125 watts or more) with anything less than their 790FX, or in some cases its little brother, the 790X.

The 790FX, provided you can find one with a SB700 or SB750 southbridge (yes the dreadful SB600 mentioned in the last article also lurks on AMD’s flagship chipset) is actually a pretty nice board. It has 32-lanes of PCI-E 2 and CrossFireX allowing you all kinds of Radeon fun, whether you go for 1, 4 or anything in between. Which brings us back to the elephant in the room; how many people spending the money on a mobo with that kind of multi-GPU support and the accompanying multiple-GPU’s will be happy with even AMD’s best CPUs? The chipset does have nice overclocking features, at least helping you get whatever is available from your $230 chip.

The 790X offers a more reasonable option for those running AMD’s 125w processors, if you can find one! I only came across one at, and though AMD’s website is pleased to tell you about the 790X, it doesn’t have any boards based on it listed in its compatibility tool. I don’t mean they don’t list them as compatible with the hungry chips: the compatibility tool has no mention of 790X boards (or for that matter, boards based on nVidia’s 710a, 720a, 730a, and 750a chipsets). The MSI K9A2 CF-F v2, which MSI claims will support 125w CPU’s (still not 140w procs though) is a lot of board for less than a hundred bucks: 2 x16 PCI-E 2 for unimpeded 2 way Crossfire performance and Gig Ethernet, but it still has the SB600 for its southbridge, and you are right back to only 4 SATA ports that don’t even work right in Vista.

If 790X boards begin to ship with SB700 or SB750 southbridges and keep prices around or under $100, they could anchor a midrange rig or budget gaming rig very well. The 790FX is likely too much board for too much money in light of the CPU’s capacity.

By nVidia: 780a SLI

Though the 780a’s southbridge outstrips the old AMD SB600 unit and the 780a comes with Hybrid-SLI as well as overall better performance than the 790FX, motherboards based on the nVidia flagship start at $240. This means buyers going this route will spend more on a motherboard than the top processor the board will run, and as the chipset’s main strength is multi-GPU performance, however many hundreds on graphics cards. The 750a SLI or lesser brethren (discussed in the article on Mainstream Chipsets for AMD CPUs) come in at price points far more in line with the AMD CPU offerings.

The 720a, 730a, and 750a all have the same Hybrid-SLI features as well as 6 SATA and 12 USB ports. Unless you need 3-Way SLI and insist on AMD processors it is hard to justify the cash outlay on the 780a.

To see how all the chipsets compare and which is the best for the system you want, continue to the Summary & Conclusion.

Further articles in this series:


Mainstream Chipset for Intel CPU’s

Enthusiast Chipset for Intel CPU’s

Mainstream Chipset for AMD CPU’s

Ethusiast Chipset for AMD CPU’s

Summary & Conclusion