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The FX-series processors
Now that we've explored Bulldozer's many code names, we should take a look at the names of the products that, you know, actual people will buy. AMD is introducing a trio of Bulldozer-based products today, and we have their vitals in the table below.

Model Cores Base core
clock speed
Turbo
clock speed
Peak Turbo
clock speed
L3 cache
size
Memory
channels
TDP Price
FX-6100 6 3.3 GHz 3.6 GHz 3.9 GHz 6 MB 2 95 W $165
FX-8120 8 3.1 GHz 3.4 GHz 4.0 GHz 8 MB 2 125 W $205
FX-8150 8 3.6 GHz 3.9 GHz 4.2 GHz 8 MB 2 125 W $245

As you can see, the clock speeds involved aren't stratospheric, but the FX-8150's peak of 4.2GHz is a fair bit higher than anything else offered by AMD or Intel these days. These products are targeted directly opposite Intel's Sandy Bridge parts, so let's have a look at the competition's lineup for comparison.

Model Cores Threads Base core
clock speed
Peak Turbo
clock speed
L3 cache
size
Memory
channels
TDP Price
Core i3-2100 2 2 3.1 GHz - 3 MB 2 65 W $117
Core i5-2320 4 4 3.0 GHz 3.3 GHz 6 MB 2 95 W $177
Core i5-2400 4 4 3.1 GHz 3.4 GHz 6 MB 2 95 W $184
Core i5-2500 4 4 3.3 GHz 3.7 GHz 6 MB 2 95 W $205
Core i5-2500K 4 4 3.3 GHz 3.7 GHz 6 MB 2 95 W $216
Core i7-2600K 4 8 3.4 GHz 3.8 GHz 8 MB 2 95 W $317

We've taken this table almost without modification from our original Sandy Bridge review early this year. Intel hasn't lowered prices on its key products once since then. The only real changes have been the additions of models to fill gaps in the original lineup, such as the addition of the Core i5-2120 at $177. We've not listed every single Sandy Bridge model above, since there are so very many. We think the ones included are the most relevant for our purposes today.

You'll notice several things about these competing lineups right away. For one, AMD has made no attempt to go after the highest-end Sandy Bridge part, the Core i7-2600K, with a Bulldozer-based offering. We expect AMD would have liked to compete at that level, but doing so apparently wasn't feasible at present. Similarly, AMD hasn't attempted to take on Intel's high-end Core i7-900-series processors. Also, notice that the top two Bulldozer-derived models are rated for 125W power envelopes, while the fastest Sandy Bridge chips have a TDP of 95W. Apparently, AMD needs the extra thermal headroom in order to compete on price and performance with the Intel products it has targeted.

With that said, the competitive match-ups are still reasonably straightforward. At $245, the FX-8150 is priced a bit above the Core i5-2500K, but the two are clearly rivals. The FX-8120 is in an interesting spot, taking on the Core i5-2500, the non-K-series version of that product, with a locked multiplier. Finally, the FX-6100 has one module disabled and a 95W TDP, and it's priced opposite the Core i5-2320.

Unfortunately, we've only managed to get our hands on one of the three initial FX-series products today, the FX-8150. You'll see a full set of results for it on the following pages, versus a host of other CPUs. We don't have a real FX-8120, but we did attempt to simulate its clock speeds and performance using AMD's Overdrive software. We're only somewhat confident that we've managed to do so successfully, but we have provisionally included some performance results for the FX-8120. Take 'em with a grain of salt, and we'll attempt to replace them with results from the real product when we can.

One more thing. In order to sweeten the pot a little, AMD has decided to unlock the multipliers on all three models of FX-series processors. That should make overclocking relatively easy to do, and it should give AMD a leg up in cases where the FX chips aren't competing with unlocked K-series parts from Intel.

The platform: Socket AM3+
As we've mentioned, Bulldozer-based CPUs should be compatible AMD's existing socket infrastructure. On the desktop, that's AMD's Socket AM3+ platform, which the company introduced back in May alongside its 9-series chipsets. FX-series processors have 942 pins, one more than older Socket AM3 CPUs, and that pin prevents them from dropping into anything but true Socket AM3+ motherboards. On the flip side, Socket AM3+ boards are capable of hosting older Socket AM3 processors like the Phenom II just fine.


The FX-8150 installed in our Asus Crosshair V mobo

If you have an existing Socket AM3+ system with an older CPU and would like to upgrade to an FX CPU, that should be possible after a quick BIOS update. The trick is that users may need to flash their BIOSes to add Bulldozer support using an older CPU before installing the new processor. That requirement generally shouldn't be a big deal for would-be upgraders, but folks who are buying new motherboards for use with an FX processor will have to hope they receive a board with an FX-capable BIOS. Otherwise, unhappy times may ensue. On that subject, AMD tells us motherboards have been shipping with Bulldozer-ready BIOSes "for some time now," and it expects any such problems with new mobos to be rare.


The FX-8150's pins and AM3+ socket

Folks who own a Socket AM3+ system with an older CPU and don't plan to upgrade will want to be careful about BIOS upgrades, too. A major mobo maker told us recently that BIOS/EFI space for adding Bulldozer support is cramped, so some features aimed at older Athlon II and Phenom II processors, such as core unlockers, may have to be deleted from newer BIOSes in order to make room. Owners of those older CPUs may want to avoid the impulse to update to the latest firmware automatically. They may be better off sticking to an older version with a full feature set for Athlon II and Phenom II CPUs. As always, you'll want to check with your motherboard maker for the final word on your board's compatibility story.

Happily, dropping an FX-series processor into a Socket AM3+ motherboard will prompt an upgrade of sorts: the board's two memory channels will then support the latest in DDR3 memory speeds, up to 1866MHz. Both Bulldozer and Llano officially support those higher memory frequencies. Intel's K-series Sandy Bridge parts are capable of working with faster RAM, too, but memory speeds above 1333MHz aren't officially blessed.