CPU Tests: Synthetic

Most of the people in our industry have a love/hate relationship when it comes to synthetic tests. On the one hand, they’re often good for quick summaries of performance and are easy to use, but most of the time the tests aren’t related to any real software. Synthetic tests are often very good at burrowing down to a specific set of instructions and maximizing the performance out of those. Due to requests from a number of our readers, we have the following synthetic tests.

Linux OpenSSL Speed: SHA256

One of our readers reached out in early 2020 and stated that he was interested in looking at OpenSSL hashing rates in Linux. Luckily OpenSSL in Linux has a function called ‘speed’ that allows the user to determine how fast the system is for any given hashing algorithm, as well as signing and verifying messages.

OpenSSL offers a lot of algorithms to choose from, and based on a quick Twitter poll, we narrowed it down to the following:

  1. rsa2048 sign and rsa2048 verify
  2. sha256 at 8K block size
  3. md5 at 8K block size

For each of these tests, we run them in single thread and multithreaded mode. All the graphs are in our benchmark database, Bench, and we use the sha256 results in published reviews.

(8-3c) Linux OpenSSL Speed sha256 8K Block (1T)(8-4c) Linux OpenSSL Speed sha256 8K Block (nT)

AMD has had a sha256 accelerator in its processors for many years, whereas Intel only enabled SHA acceleration in Rocket Lake. That's why we see RKL matching TR in 1T mode, but when the cores get fired up, TR and TR Pro streak ahead with the available performance and memory bandwidth. This is all about threads here, and 128 threads really matters.

GeekBench 5: Link

As a common tool for cross-platform testing between mobile, PC, and Mac, GeekBench is an ultimate exercise in synthetic testing across a range of algorithms looking for peak throughput. Tests include encryption, compression, fast Fourier transform, memory operations, n-body physics, matrix operations, histogram manipulation, and HTML parsing.

I’m including this test due to popular demand, although the results do come across as overly synthetic.

(8-1c) Geekbench 5 Single Thread(8-1d) Geekbench 5 Multi-Thread

DRAM Bandwidth

As we're moving from 2 channel memory on Ryzen to 4 channel memory on Threadripper then 8 channel memory on Threadripper Pro, these all have associated theoretical bandwidth maximums but there is a case for testing to see if those maximums can be reached. In this test, we do a simple memory write for peak bandwidth.

For 2-channel DDR4-3200, the theoretical maximum is 51.2 GB/s.
For 4-channel DDR4-3200, the theoretical maximum is 102.4 GB/s.
For 8-channel DDR4-3200, the theoretical maximum is 204.8 GB/s.

(8-2b) AIDA DRAM Write Speed

Here we see all the 4-channel Threadripper processors getting around 83 GB/s, but the Threadripper Pro can only achieve closer to its maximums when there are more cores present. Along with the memory controller bandwidth, AMD has to manage internal infinity fabric bandwidth and power to get the most out of the system. The fact that the 64C/64T achieves better than the 64C/128T might suggest that in 128T there is some congestion.

CPU Tests: Legacy and Web CPU Tests: SPEC
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  • Thanny - Thursday, July 15, 2021 - link

    Your Blender results for the 3960X are off by a lot. I rendered the same scene with mine in 173 seconds. That's with PBO enabled, so it'll be a bit faster than stock, but not 20% faster.

    My guess is that you didn't warm Blender up properly first. When starting a render for the first time, it has to do some setup work, which is timed with the rest of the render, but only needs to be done once.

    I'd expect a stock 3960X to be in the neighborhood of 180 seconds.
  • 29a - Thursday, July 15, 2021 - link

    "Firstly, because we need an AI benchmark, and a bad one is still better than not having one at all."

    I 100% disagree with this statement. Bad data is worse than no data at all.
  • arashi - Saturday, July 17, 2021 - link

    But but but what about the few (<10) clicks they'd lose for not having lousy CPU based AI benchmarks!
  • willis936 - Thursday, July 15, 2021 - link

    Availability of entry level ECC CPUs (AMD pro and Intel Xeon E-2200/W) is really low. It's unfortunate. People don't have the cash for $10k systems right now but the need for ECC has only gone up. I hope for more editorials calling for mainstream ECC.
  • Threska - Thursday, July 15, 2021 - link

    Linus is mainstream enough.

    https://arstechnica.com/gadgets/2021/01/linus-torv...
  • Mikewind Dale - Thursday, July 15, 2021 - link

    At least mainstream desktop Ryzens tend to support ECC, even if not officially validated.

    What frustrates me is that laptop Ryzens don't support ECC at all - not even the Ryzen Pros.

    Every Ryzen Pro laptop I've seen lacks ECC support, and some of them even have non-ECC memory soldered to the motherboard.

    If you want an ECC laptop, it appears you have literally no choice at all but a Xeon laptop for $5,000.
  • mode_13h - Friday, July 16, 2021 - link

    > laptop Ryzens don't support ECC at all - not even the Ryzen Pros.

    It probably depends on the laptop. If its motherboard doesn't have the extra traces for the ECC bits, then of course it won't.
  • Mikewind Dale - Saturday, July 17, 2021 - link

    It depends on the laptop, yes. But I haven't found a single Ryzen Pro laptop from a single company that supports ECC.

    AMD's website ("Where to Buy AMD Ryzen™ PRO Powered Laptops") lists HP ProBook, HP EliteBook, and Lenovo Thinkpad. But none of them support ECC.
  • mode_13h - Saturday, July 17, 2021 - link

    > I haven't found a single Ryzen Pro laptop from a single company that supports ECC.

    Thanks for the datapoint. Maybe someone will buck the trend, but it's also possible they judged the laptop users who really care about ECC would also prefer a dGPU and therefore won't be using APUs.
  • mode_13h - Friday, July 16, 2021 - link

    > I hope for more editorials calling for mainstream ECC.

    You'll probably just get inferior in-band ECC.

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