AMD was active in the datacenter business for years, but their latest big release was in 2012, with the Abu Dhabi Opteron. Ever since Intel owns 99% of the market share, with the Xeon family, not even the promising ARM based processors could change this. AMD also tried with ARM cores in x86 processors, but the project known as Project Skybridge was shut down in 2015.
ZEN cores in the server processors
This year AMD faces Intel with it’s new Zen core based family called EPYC. It seems very promising after RYZEN spiced up the desktop PCs. They announced the new generation previously, but the new features, spec was only recently revealed. They offer 1- and 2-socket solutions for the newly shaken server market, to bring the fight to their competitors.
At the announcement of the new EPYC series, the top four CPUs were revealed, focusing on dual socket systems. The full range of the EPYC family will consist of twelve processors, with three for single socket environments.
Under the cover there are four silicon dies, each containing one of the 8-core silicon we saw in the Ryzen processors. Each silicon has two core complexes, with four cores each, and supports two memory channels, totaling to a maximum of 32 cores and 8 memory channels on an EPYC processor.
AMD’s new interconnect called “Infinity Fabric” is connecting the dies and also plays a key role in processor-to-processor communication. They designed the infinity fabric to be modular and scalable to help the support of forecoming large CPUs and GPUs.
The ability to support up to 8 memory channels and support for 2 DIMMs per channel, AMD is quoting a 2TB per socket maximum memory support per socket. This means a 4TB maximum memory available in a two socket solution on 32 DIMM slots.
Each processor supports 128 PCIe 3.0 lanes, that is enough for six GPUs with full bandwith support or 32 NVMe drives for storage. The PCIe lanes can be used for IO devices, such as SATA or network ports, or as Infinity Fabric connections to other devices. They also feature 4 IO hubs for each CPU for high bandwidth, and full PCIe P2P support.
In the two processor systems they use 64 of the available PCIe lanes to communicate through the Infinity Fabric. This means, that there is still 128 PCIe lanes to use in the system, and the memory support is doubled.
Nine of the new models are designed for dual processor systems, while the remaining 3 will be available for single socket solutions. AMD haven’t launched a quad socket system, since the 90-95% of the market is populated with single and dual socket solutions.
According to AMD some dual processor systems can be replaced with a single socket EPYC system, thanks to the increased IO handling capabilities and better memory support.
Processors for dual socket systems:
|CPU cores/threads||CPU clock speed/boost||L3 cache||Memory support||PCIe 3.0 lanes||TDP (W)||Price (USD)|
|EPYC 7601||32/64||2,2/3,2 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||180||>4000|
|EPYC 7551||32/64||2/3 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||180||>3200|
|EPYC 7501||32/64||2/3 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||155/170||?|
|EPYC 7451||24/48||2,3/3,2 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||180||>2400|
|EPYC 7401||24/48||2/3 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||155/170||>1700|
|EPYC 7351||16/32||2,4/2,9 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||155/170||>1100|
|EPYC 7301||16/32||2,2/2,7 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||155/170||>800|
|EPYC 7281||16/32||2,1/2,7 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||155/170||>600|
|EPYC 7251||8/16||2,1/2,9 GHz||64 MB||DDR4/2666 MHz||8×16 (128)||120||>400|
Processors for single socket systems:
|CPU cores/threads||CPU clock speed/boost||L3 Cache||Memory Support||PCIe 3.0 lanes||TDP (W)||Price (USD)|
|EPYC 7551P||32/64||2/3 GHZ||64 MB||DDR4-2666 MHz||8×16 (128)||180||>2000|
|EPYC 7401P||24/48||2/3GHz||64 MB||DDR4-2666 MHz||8×16 (128)||155/170||>1000|
|EPYC 7351P||16/32||2,4/2,9 GHz||64 MB||DDR4-2666 MHz||8×16 (128)||155/170||>700|
But how does it perform?
AMD’s own benchmarks (1,2) speaks of World Records, where they are comparing the new series to a Xenon E5-V4. In the first benchmark they compared two socket servers with an AMD EPYC 7601 with 64 cores, running on 2,2 GHz with an Intel Xeon E5-2699A V4 with 44 cores running on 2,4 GHz.
They used SPECINT®_RATE2006 and SPECFP®_RATE2006 to test the configurations. In the floating point test AMD’s setup scored 1840 point vs Intel’s 1160, what means up to 59% improvement. In integer performance EPYC reached 2360 points against Intel’s 1890, in this case AMD provided up to 25% better performance.
In the next test, two one socket configurations collided. AMD’s EPYC 7601 with 32 cores, running on 2,2 GHz against the Intel Xeon E5-2699 V4 with 22 cores, running at 2,4 GHz. In this configuration, the floating point tests are 943 to 568 for AMD’s advantage, therefore producing a 66% better result. The integer test resulted in 1200 points for AMD and 909 points for Intel’s Xeon, where Intel was beaten by 32%.
In their next session of benchmarking they compared the memory bandwidth of the three server configuration. They tested AMD’s one socket configuration with an EPYC 7601 with 32 cores running at 2,2 GHz, with 512 GB memory, AMD’s two socket configuration with two EPYC 7601 with 64 cores running on 2,2 GHz with 512 GB system memory and Intel’s Xeon E5-2690 V4 with it’s 44 cores running on 2,4 GHz with 256 GB memory. The results are in the following table:
|Results||AMD’s 1 socket configuration||AMD’s 2 socket configuration||Intel’s 2 socket configuration||Improvement from AMD 1 socket to Intel 2 socket||Improvement from AMD 2 socket to Intel 2 socket|
The results are really promising, but all of them were based on AMD’s internal testing, therefore it is advised to wait for more independent benchmark results before jumping to final conclusions.
The new processor will be available to the public shortly, with all of the models accessible at the end of July.