The Bulldozer Review: AMD FX-8150 Tested
by Anand Lal Shimpi on October 12, 2011 1:27 AM ESTCache and Memory Performance
I mentioned earlier that cache latencies are higher in order to accommodate the larger caches (8MB L2 + 8MB L3) as well as the high frequency design. We turned to our old friend cachemem to measure these latencies in clocks:
| Cache/Memory Latency Comparison | ||||||
| L1 | L2 | L3 | Main Memory | |||
| AMD FX-8150 (3.6GHz) | 4 | 21 | 65 | 195 | ||
| AMD Phenom II X4 975 BE (3.6GHz) | 3 | 15 | 59 | 182 | ||
| AMD Phenom II X6 1100T (3.3GHz) | 3 | 14 | 55 | 157 | ||
| Intel Core i5 2500K (3.3GHz) | 4 | 11 | 25 | 148 | ||
Cache latencies are up significantly across the board, which is to be expected given the increase in pipeline depth as well as cache size. But is Bulldozer able to overcome the increase through higher clocks? To find out we have to convert latency in clocks to latency in nanoseconds:
We disable turbo in order to get predictable clock speeds, which lets us accurately calculate memory latency in ns. The FX-8150 at 3.6GHz has a longer trip down memory lane than its predecessor, also at 3.6GHz. The higher latency caches play a role in this as they are necessary to help drive AMD's frequency up. What happens if we turn turbo on and peg the FX-8150 at 3.9GHz? Memory latency goes down. Bulldozer still isn't able to get to main memory as quickly as Sandy Bridge, but thanks to Turbo Core it's able to do so better than the outgoing Phenom II.
L3 access latency is effectively a wash compared to the Phenom II thanks to the higher clock speeds enabled by Turbo Core. Latencies haven't really improved though, and Bulldozer has a long way to go before it reaches Sandy Bridge access latencies.
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Ryan Smith - Wednesday, October 12, 2011 - link
Good point. Fixed.Marburg U - Wednesday, October 12, 2011 - link
they have a bloating cache with something wrong insidehttp://www.xbitlabs.com/images/cpu/amd-fx-8150/t5....
npp - Wednesday, October 12, 2011 - link
Sun went an even more extreme route regarding FP performance on its Niagara CPUs - as far as I remember, the first generation chip had a single FPU shared across eight cores. Performance was not even close to a dual-core Core 2 Duo at that time. So that was what I though when I first read about the "module" approach in Bulldozer maybe an year ago - man, this must be geared towards server workloads primary, it will suffer on the desktop. I guess FPU count = core count would have be more appropriate for the FX line.hasu - Wednesday, October 12, 2011 - link
Would this be a good candidate for web server applications because of its excellent multi-threaded performance? How about to host a bunch of Virtual Machines?sep332 - Wednesday, October 12, 2011 - link
I've also been wondering if running a lot of VMs would work better on this CPU. But I don't really know how you'd benchmark that kind of thing. Time and total energy consumption to serve 20,000 web pages from 12 VMs?magnetik - Wednesday, October 12, 2011 - link
I've been waiting for this moment for months and months.Reading the whole thing now...
themossie - Wednesday, October 12, 2011 - link
This processor is worse than the Phenom II X6 for most of my workloads. My next machine will be Sandy/Ivy Bridge.But... we haven't seen this clock ramp up yet. As Anand mentions on page 3 - Remember the initial Pentium 4s? The Williamette 1.4 and 1.5 ghz processors were clearly worse than the competition, to say nothing of the PIII line. In time the P4 consistently beat the much higher IPC AMD processors on most workloads, especially after introducing Hyper-threading. This really does feel like a new Pentium IV! Trying a design based on clock speed and one-upping Intel's hyperthreading by calling 4 '1.5' cores 8 (we hyperthread your hyperthreading!) - it will be a wild ride.
At this point, I don't see anyone beating Intel at process shrink and they're a moving target. But competitive pricing, quick ramp up and a few large server wins can still save the day. Dream of crazy clockspeeds :-)
themossie - Wednesday, October 12, 2011 - link
Upon further reflection...- Expect to see Bulldozer targeted towards servers and consumers who think "8 cores" sounds sexy, at least until clockspeed ramps up.
- Processor performance is not the limiting factor for most consumer applications. AMD will push APUs very heavily, something they can beat Intel at. Piledriver should drive a good price/performance bargain for OEMs, and for laptops may have idle power consumption in shouting distance of Sandy Bridge.
I'm more optimistic about AMD now. But my next machine will still be Sandy Bridge / Ivy Bridge.
wolfman3k5 - Wednesday, October 12, 2011 - link
I see people that say that they'll be waiting for Piledriver. Why not wait for AMD Drillbit, or AMD Dremel? How about AMD Screwdriver or AMD Nailpuller? Tomorrow my 2600K arrives. I'm done. I had a build ready with a ASUS 990FX ready for Bulldozer, but I will "bulldoze" the part back to NewEgg.I must admit, I was worried when I saw the large amounts of L2 cache before the launch. AMD engineers must have been taking the summer off, and decided to throw more cache at the problem. AMD needs a new engineering team. Why the hell can Intel get it right and they can't?
AMD, your CPU engineers are lazy and incompetent. I mean, it only took you "only" four years to get your own version of the Pentium 4.
The bottom line is that its time to fire your lazy retarded and incompetent engineers, and scout for some talent. That's what every other company does that wants to succeed, regardless of the industry. I mean, look at KIA and Hyundai for example, they went out and hired the best designers from Audi and the best engineers they could buy with money. Throw some more money at the problem AMD and solve your problems. And if those lazy fat fucks in Texas that you call engineers don't deliver, look somewhere else. Israel or Russia maybe? Who knows... Just my 2 cents.
IKeelU - Wednesday, October 12, 2011 - link
I know nothing of AMD employee's work ethic, but...their problems may have nothing to do with raw technical talent. But you are right about one thing - throwing money at a problem can be helpful, and that's likely why Intel has succeeded for so long. Intel has a lot of cash, and a lot of assets (such as equipment). They can afford the best design/debugging tools (whether they buy'em or make'em), which makes it much easier to develop a top product given the same amount of microchip engineering talent.And just because they're based in Texas doesn't mean their staff is all-American. Like most US tech firms, quite a bit of their talent was probably imported.