(No images or videos yet, sorry. This was basically my morning project.)
For those who have not heard, or have not been paying attention, AMD decided to release some Excavator cores to the market. They are basically cannibalized/salvaged cores that are still good, but the rest of the chip failed to make the binning process, so the integrated GPU and Southbridge are disabled, and the die is slapped onto the appropriate PGA format. The goods news is that IPC has been improved, along with some of the cache issues that plagued the Bulldozer family of processors. The bad news is a limit of x8 PCIe lanes, and 2MB of L2 Cache. (Also, potentially a slightly gimped memory controller, but more on that later.)
When the Athlon X4 845 was first released in late February, I snagged one up, perhaps too hastily. Although it arrived by March 10th, it was just last week that Gigabyte finally released their (beta) BIOS update that allowed for Carrizo support for my particular motherboard, the F2A88X-UP4. Some of their other products, like the newly released FM2+ boards with USB 3.1 support, already had updates, along with their G1.Sniper board, but, for whatever reason, the UP4 was put on the backburner. Most annoying! (For those that care, ASUS has allowed for Carrizo support for all their boards for roughly a month, and ASRock followed suit a couple weeks ago. MSI, like Gigabyte, is still mixed.)
Anyway, let's get to the meat and potatoes.
Test set-up:
Athlon x4 845
Gigabyte F2A88X-UP4
G.skill DDR3 2400 Trident X
Gigabyte R9 285
Cooling:
Thermalright Silver Arrow IB-E. (Why? Because I could.)
Meat and Potatoes
My tool of choice was IntelBurnTest, and from this program I'm going to share some numbers (from the standard test). Not an end-all-be-all metric, but it's what I have to offer, currently.
At stock speeds, with its 3.8ghz boost, the Athlon x4 845 managed to hash out 22.5 GFlops, which matched my previous CPU, the Athlon x4 760K, when it was overclocked to 4.7ghz.
With a 108 base clock, I obtained a ~3.8ghz base clock, with a ~4.1ghz boost clock, which hashed out roughly 24.5 GFlops. This required 1.462V on the Vcore, and 1.2 volts to the NB. At 110mhz on the baseclock, I managed to boot, but could not successfully pass any tests with IBT, regardless of the voltage I crammed into the componentry - all the way up to 1.55 volts.
Side Notes and Stream of Consciousness
Overclocking on the FM2+ platform, without an unlocked multiplier, is a giant pain in the dick. All of the I/O of the Fusion Controller Hub (FCH) is attached to the Base Clock, with no way of separating it. This means that only a small boost is possible before your rig starts throwing fits at you, because the clock rate is affecting how the USB, SATA, and PCIe operate. SATA is the most finicky, and those who have the patience can try switching to IDE Mode (as opposed to AHCI) to have some more leeway.
Furthermore, overclocking with AMD on any of their newer CPUs that were released after their Piledriver/Trinity line-up has its own set of problems. Since they have more telemetry devices installed that attempt to provide a more smooth-grained approach for performance optimization and thermals, you can get some wonky throttling results when you still have plenty of leeway on both the Core and Socket temperatures. These weird results are mostly regulated to heavy stress testing programs, like Prime95 and IBT, and light day-to-day tasks usually don't have this effect.
To confound matters, the 845 refused to boot on either of the G.skill RAM's overclocked profiles. I had to dial back the frequency to 2133, from 2400. Apparently, others have run into this issue, and it has been theorized that the cause is because the product is essentially a salvaged mobile component with a lesser memory controller.
While there are other (more indepth and professional) reviews that show the small, but measurable, affects that having access to only x8 PCIe lanes and less L2 cache, the perceived difference is negligible. Even after I run through a test suite of gaming and benchmarks, I don't think I'll notice much of a difference, and the effort will be spend mostly in the pursuit of bigger, higher numbers.