AMD Zen 2 Microarchitecture Analysis: Ryzen 3000 and EPYC Rome
by Dr. Ian Cutress on June 10, 2019 7:22 PM EST- Posted in
- CPUs
- AMD
- Ryzen
- EPYC
- Infinity Fabric
- PCIe 4.0
- Zen 2
- Rome
- Ryzen 3000
- Ryzen 3rd Gen
Floating Point
The key highlight improvement for floating point performance is full AVX2 support. AMD has increased the execution unit width from 128-bit to 256-bit, allowing for single-cycle AVX2 calculations, rather than cracking the calculation into two instructions and two cycles. This is enhanced by giving 256-bit loads and stores, so the FMA units can be continuously fed. AMD states that due to its energy aware scheduling, there is no predefined frequency drop when using AVX2 instructions (however frequency may be reduced dependent on temperature and voltage requirements, but that’s automatic regardless of instructions used)
In the floating point unit, the queues accept up to four micro-ops per cycle from the dispatch unit which feed into a 160-entry physical register file. This moves into four execution units, which can be fed with 256b data in the load and store mechanism.
Other tweaks have been made to the FMA units than beyond doubling the size – AMD states that they have increased raw performance in memory allocations, for repetitive physics calculations, and certain audio processing techniques.
Another key update is decreasing the FP multiplication latency from 4 cycles to 3 cycles. That is quite a significant improvement. AMD has stated that it is keeping a lot of the detail under wraps, as it wants to present it at Hot Chips is August. We’ll be running a full instruction analysis for our reviews on July 7th.
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jamescox - Saturday, June 22, 2019 - link
You seem to just be trying to spread FUD. Also, you don’t seem to know how long a nanosecond is. The CCX to CCX latency can cause slower performance for some badly written or or badly optimized multithreaded code, but it is on such a fine scale that it would just effect the average frame rate. It isn’t going to cause stuttering as you describe.The stuttering you describe could be caused by a huge number of things. It could be the gpu or cpu thermally throttling due to inadequate cooling. If the gpu utilization goes down low, that could be due to the game using more memory than the gpu has available. That will slow to a crawl while assets are loaded across the pci express bus. So, if anyone is actually having this problem, check your temperatures, check your memory usage (both cpu and gpu), then maybe look for driver / OS issues.
playtech1 - Wednesday, June 12, 2019 - link
Good products and good prices.Knock-out blow though? I don't think so for the consumer and gaming space, as I can buy a 9900 today for a fairly small premium over the price of a 3800x and get basically the same performance.
The 12 and 16 core chips look more difficult for Intel to respond to though, given how expensive its HEDT line is (and I say that as an owner of a 7860x).
Atari2600 - Wednesday, June 12, 2019 - link
Yeah, power and thermals are not so important in consumer/game space.In server/HPC, Intel is in deep crap.
Phynaz - Wednesday, June 12, 2019 - link
Bahahaha. No.eva02langley - Thursday, June 13, 2019 - link
Phhh... are you ban from WCCFtech?Gastec - Wednesday, June 19, 2019 - link
I guess I'm neither consumer nor gamer with my i7-860 and GTX 670, G502, G110 and G13. I bought the Logitech G13 just to type better comments on Tweeter :PGastec - Wednesday, June 19, 2019 - link
I also turn OFF RGB whenever I can, anti-cosumerism and anti-social is written on my forehead and everyone is pointing at me on the woke streets.just4U - Thursday, June 13, 2019 - link
I'd say it's a substantial blow to Intel. One of the reasons I picked up a 2700x was the cooler, which is pretty damn good overall.. and the buy in was substantially lower. The 3700x-3800x will only add to that incentive with increased performance (most will likely not even notice..)Drop in the 12-16 core processors (provided there are no tradeoffs for those additional cores..) make the 9900k unappealing on all fronts. The 9700K was a totally unappealing product with it's 8c/8t package..already and after this launch won't make sense at all.
Gastec - Thursday, June 20, 2019 - link
Core i9-9900 I presume. Nowhere to be found for sale in Mordor. Only found one on Amazon.com for $439.99 reduced from $524.95, sold by "Intel" whomever that scammer is.Hamza12786 - Thursday, June 13, 2019 - link
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