AMD Carrizo Part 2: A Generational Deep Dive into the Athlon X4 845 at $70
by Ian Cutress on July 14, 2016 9:00 AM ESTReal World Performance at 3 GHz
For our generational testing, we took each of the four main processors in this test and adjusted their CPU frequencies in the BIOS to 3 GHz. This was achieved through a 30x multiplier and 100 MHz base frequency, which for each processor is a reduction from the stock speeds. We set each CPU to perform at 3 GHz only to fix the frequency, and ran the memory in each case at the maximum supported frequency by the processor. Some benchmarks in the generational tests will probe the memory, and an upgrade in the memory controller to support higher frequencies (officially) than an older processor is, a generational upgrade, as important as the core or cache performance.
| AMD CPUs | ||||||||||||
| µArch / Core |
Cores | Base Turbo |
TDP | DDR3 | L1 (I) Cache |
L1 (D) Cache |
L2 Cache |
|||||
| Athlon X4 845 |
Excavator Carrizo |
4 | 3500 3800 |
65 W | 2133 | 192KB 3-way |
128KB 8-way |
2 MB 16-way |
||||
| Athlon X4 860K |
Steamroller Kaveri |
4 | 3700 4000 |
95 W | 1866 | 192KB 3-way |
64KB 4-way |
4 MB 16-way |
||||
| Athlon X4 760K |
Piledriver.v2 Richland |
4 | 3800 4100 |
100 W | 1866 | 128KB 2-way |
64KB 4-way |
4 MB 16-way |
||||
| Athlon X4 750K |
Piledriver Trinity |
4 | 3400 4000 |
100 W | 1866 | 128KB 2-way |
64KB 4-way |
4 MB 16-way |
||||
Speaking of cache, as mentioned at the beginning of this review, the Athlon X4 845 has a significant advantage in the L1 cache layout, affording a 2x size L1 data cache along with a move from 4-way to 8-way associativity. Each of these methods, as a broad rule of thumb, typically decreases the cache miss rate by a factor of 1.414 (square root of 2x). Combined should see a factor two decrease in cache misses overall, and this will affect a number of benchmarks when we compare each processor at a fixed frequency. On the other side of the equation, the L2 cache for the X4 845 is half that of the X4 860K, meaning that if the data is not in the L1, it is less likely to be in the L2, which will add additional latency.
Dolphin Benchmark: link
Many emulators are often bound by single thread CPU performance, and general reports tended to suggest that Haswell provided a significant boost to emulator performance. This benchmark runs a Wii program that raytraces a complex 3D scene inside the Dolphin Wii emulator. Performance on this benchmark is a good proxy of the speed of Dolphin CPU emulation, which is an intensive single core task using most aspects of a CPU. Results are given in minutes, where the Wii itself scores 17.53 minutes.
Emulation takes cues from a high IPC and base frequency, however for our generational testing it is all about the microarchitecture. The Carrizo has a 9% advantage here over the Kaveri.
WinRAR 5.0.1: link
Our WinRAR test from 2013 is updated to the latest version of WinRAR at the start of 2014. We compress a set of 2867 files across 320 folders totaling 1.52 GB in size – 95% of these files are small typical website files, and the rest (90% of the size) are small 30 second 720p videos.
WinRAR enjoys memory bandwidth with its variable workload, and seemingly the Kaveri has a strong showing here. The Carrizo only has 2MB of L2 cache, which most likely puts it at a disadvantage.
3D Particle Movement v2
The second version of this benchmark is similar to the first, however it has been re-written in VS2012 with one major difference: the code has been written to address the issue of false sharing. If data required by multiple threads, say four, is in the same cache line, the software cannot read the cache line once and split the data to each thread - instead it will read four times in a serial fashion. The new software splits the data to new cache lines so reads can be parallelized and stalls minimized. As v2 is fairly new, we are still gathering data and results are currently limited.
We saw this in our laptop Carrizo testing: if we adjust the software to avoid false sharing (which decreases performance), the Excavator microarchitecture pulls a significant lead in 3DPMv2. Part of this is most likely down to the larger L1 data cache as well.
Web Benchmarks
On the lower end processors, general usability is a big factor of experience, especially as we move into the HTML5 era of web browsing.
WebXPRT 2013
This benchmark can be memory intensive, as it draws various graphs and applies filters to pictures, among other things. The lower L2 cache hurts here.
Google Octane v2
In contrast, Octane attempts to stay as close to the execution ports as possible, and the Carrizo cores take an 18% lead over Kaveri.
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The_Countess - Tuesday, July 19, 2016 - link
actually bulldozer on 14nm would have been a completely different beast. it would have allowed AMD to use far more transistors per core while still making it way smaller in terms of size. that would have allowed AMD to create a far wider execution core, eliminating most of its bottlenecks.the high latency cache would probably still means it wouldn't be great for games but for everything else it would be a far more competitive design.
it is also 14nm that will allow zen to make such a massive leap in IPC's as it will be a very wide Core, while still being pretty small, something that just can't be done on 28nm.
bulldozer might not have been the best idea, but being stuck on 32/28nm for so long made all it's issues infinitely worse.
nandnandnand - Thursday, July 14, 2016 - link
"Well better late than never for Andantech,"There was no point in Adanantech writing this review, because it is a chip for those people too stupid to wait until Zen. Zen is the only thing that matters.
BurntMyBacon - Friday, July 15, 2016 - link
@nandnandnand: "There was no point in Adanantech writing this review, because it is a chip for those people too stupid to wait until Zen. Zen is the only thing that matters."Now, because this review exists, people as yet uninformed have concrete data to avoid decisions that might make them look (as you put it) stupid. There is very much a point.
Byte - Thursday, July 14, 2016 - link
Zen will probably be the RX480 in the CPU world. Better performance, still trounced by the competition, but competently priced.looncraz - Friday, July 15, 2016 - link
That would be an improvement on the current situation. AMD is pricing their CPUs quite poorly right now.An Intel Celeron G3900 is $50 right now. AMD's closest competition is the A6-7400k - at $55.
Both are dual cores, both are 65W, both have middling (but usable) graphics performance... quite similar at first glance... except the Intel runs at 2.8Ghz and the AMD runs at 3.5Ghz w/ 3.9Ghz turbo and can rather easily exceed 4Ghz when overclocked.
Sounds like AMD should be taking home the gold on that one, until you find that the Celeron is nearly 25% faster in single threaded programs and is ~40% faster in multi-threaded programs... Bad deal going for the AMD... especially since the same board that hosts the Celeron can accept much faster CPUs and the AMD board simply doesn't have notably more powerful options available - you can upgrade to a quad core, but you won't be getting better single threaded performance no matter how hard you try. You might break even around 5Ghz, if you can manage it...
AMD has a 40% clock-speed advantage out the gate, but loses by a large margin.
bananaforscale - Friday, July 15, 2016 - link
You know what's funny? The fact that if I want to get a CPU that's faster than the FX-6100 I bought almost 5 years ago I still have to pay more than what I paid for it. Sure, Intel gives better single thread performance but I'd get fewer cores and no overclockability. Then there's the fact that I've been running that original Bulldozer with a 20% OC and it seems more stable than at stock clocks.Comparing single data points tells nobody a thing. Anyway, isn't that A6 in your comparison unlocked? :P
wumpus - Friday, July 15, 2016 - link
I'm sure you missed an FX-8320 sale, or you really nailed the low point. Unfortunately Intel can match AMD's performance at nearly the same price, and is cutting off AMD's air supply that way.artk2219 - Monday, July 18, 2016 - link
Whats crazy is that Microcenter sells the FX 8320E's for $89.99. They also have a motherboard bundle option that you can get for $125 to $170 depending on which board you choose. Theoretically you can get a processor, motherboard, cooler, and memory for the price of a non-K core I5, or just a motherboard and processor for the price of an I3. The unfortunate thing is that not everyone has a microcenter near them, but for the ones that do you can get quite the deal, especially since those 8320E's will easily OC to FX 8350 levels, and more likely 4.2 to 4.6 from a stock clock of 3.2BlueBlazer - Friday, July 15, 2016 - link
From the leaks plus AMD's vague announcements, all points to AMD's Zen is going to be quite late (right into 2017). Why put use 28nm "placeholder" for AM4 if Zen is due soon? Also Global Foundries only has 14nm LPP which is a low power process. That may mean the frequency is going to be low (just look at the chips made on 14nm LPP like Qualcomm's Snapdragon 820, or even AMD's latest Radeon RX480). Reference http://semiengineering.com/high-performance-and-lo... quote "The “LP” processes are optimized for low power and feature design rules targeted for the lowest leakage, support lower operative voltages, and tend to have the slowest transistors of the three options".wiboonsin - Sunday, November 12, 2017 - link
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