Expensive Quad Sockets vs. Ubiquitous Dual Sockets
by Johan De Gelas on October 6, 2009 1:00 AM EST- Posted in
- IT Computing
What Intel and AMD Are Offering
Before we can dive into benchmarks, it is good to see how the vendors position their CPUs. Before we do that, here's a quick spec sheet overview of the most important AMD and Intel CPUs.
| Processor Speed and Cache Comparison | |||||
| Model | Number of cores |
Clock speed | L2 Cache (KB) | L3 Cache (MB) | Interconnect Bandwidth (one direction) |
| AMD Opteron 8439 SE | 6 | 2.8 | 6 x 512 KB | 6MB | 9.6GB/s |
| Intel Xeon X7460 | 6 | 2.66 | 3 x 3MB | 16MB | Via FSB & chipset |
| AMD Opteron 8435 | 6 | 2.6 | 6 x 512 KB | 6MB | 9.6GB/s |
| Intel Xeon E7450 | 6 | 2.4 | 3 x 3MB | 12MB | Via FSB & chipset |
| AMD Opteron 8431 | 6 | 2.4 | 6 x 512 KB | 6MB | 9.6GB/s |
| Intel Xeon E7440 | 4 | 2.4 | 2 x 3MB | 16MB | Via FSB & chipset |
| AMD Opteron 8389 | 4 | 2.9 | 4 x 512 KB | 6MB | 8.8GB/s |
| Intel Xeon E7430 | 4 | 2.13 | 2 x 3MB | 12MB | Via FSB & chipset |
| Intel Xeon E7420 | 4 | 2.13 | 2 x 3MB | 8MB | Via FSB & chipset |
Excluding the low power models, AMD offers three hex-core CPUs and Intel offers two. The gap between the top Xeon models and the midrange is remarkable: the 7440 only has four cores. That means that there is probably - roughly estimated - a gap of 30 to 50% performance between the 7440 and 7450. That gap does not exist in the AMD line-up: the Opteron 8389 has also four cores but clocks 21% higher than the 8431. The performance gap is therefore small. The pricing reflect our remarks:
| Pricing | |||||
| Intel Xeon Model | Speed (GHz) / TDP (W) |
Price | AMD Opteron Model | Speed (GHz) / ACP (W) |
Price |
| Hex-Core | |||||
| X7460 | 2.66/ 130W | $2729 | 8439 SE | 2.8 / 105-125W | $2649 |
| 8435 | 2.6 / 75 - 115W | $2649 | |||
| E7450 | 2.4 / 90W | $2301 | 8431 | 2.4 /75 - 115W | $2149 |
| Quad-Core | |||||
| E7440 | 2.4 / 90W | $1980 | 8389 | 2.9 / 75- 115W | $2149 |
| E7430 | 2.13 / 90W | $1391 | 8387 | 2.7 / 75 -115W | $1865 |
| E7420 | 2.13 / 90W | $1177 | 8378 | 2.4 / 75 -115W | $873 |
| Dual Sockets | |||||
| X5570 | 2.93 / 95W | $1386 | |||
| X5550 | 2.66 / 95W | $958 | 2435 | 2.6 / 75-115W | $989 |
AMD feels that the E7450 is no match for the 8435. As a result, the latter comes with a pretty heavy price tag. Whether this is justified is easy to check, even if we do not test the E7450 in this review. As the E7450 is the same die as the X7460 at a slightly lower voltage and clock speed, the E7450 is about 7 to 8% slower than the X7460. The 2.4GHz 8378 is quite interesting: still clocked at a decent 2.4GHz, it is by far the cheapest quad socket processor. As the number of VMs that you can run on a server is often limited by the amount of memory and not processor power, a quad 8378 might make sense.
The question remains whether the best dual socket processors of Intel or AMD are a threat to the quad socket servers. Two X5570 will set you back less than $2800, while four Xeon E7420 start at $4700. Even a relatively entry-level X7430 2.13GHz based server (32GB, 4 CPUs) will cost in the range of $13000. That is three times as much as similar dual 2435 servers and 2.6 times as much as a dual X5550 machine. That is why we include the fastest dual socket machines in this test too.
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rbbot - Tuesday, October 6, 2009 - link
Surely the high price of 8GB Dimms isn't going to last very long, especially with Samsung about to launch 16GB parts soon.Calin - Wednesday, October 7, 2009 - link
8GB DIMMs have two markets: one would be upgrade from 4GB or 2GB parts in older servers, the other would be more memory in cheaper servers. As the demand can be high, it all depends on the supply - and if the supply is low, prices are high.So, don't count on the price of 8GB DIMMs to decrease soon
Candide08 - Tuesday, October 6, 2009 - link
One performance factor that has not improved much over the years is the decrease in percentage of performance gains for additional cores.A second core adds about 60% performance to the system.
Third, fourth, fifth and sixth cores all add lower (decreasing) percentages of real performance gains - due to multi-core overhead.
A dual socket dual core system (4 processors) seems like the sweet spot to our organization.
Calin - Wednesday, October 7, 2009 - link
If your load is enough to fit into four processors, then this is great. However, for some, this level of performance is not enough, and more performance is needed - even if paying four times as much for twice as much performancehifiaudio2 - Tuesday, October 6, 2009 - link
FYI the R710 can have up to 192gb of ram...12x16GB
not cheap :) but possible
JohanAnandtech - Tuesday, October 6, 2009 - link
at $300 per GB, or the price of 2 times 4 GB DIMMs, I don't think 16 GB DIMMs are going to be a big success right now. :-)wifiwolf - Wednesday, October 7, 2009 - link
for at least 5 years you meanmamisano - Tuesday, October 6, 2009 - link
Great article, just have a question about the power supplies. Why do the quad-core servers need a 1200W PSU if the highest measured load was 512W? I know you would like to have some head-room but it looks to me that a more efficient 750 - 900W PSU may have provided better power consumption results... or am I totally wrong? :)JarredWalton - Tuesday, October 6, 2009 - link
Maximum efficiency for most PSUs is obtains at a load of around 40-60% (give or take), so if you have a server running mostly under load you would want a PSU rated at roughly twice the load power. (Plus a bit of headroom, of course.)JohanAnandtech - Wednesday, October 7, 2009 - link
Actually, the best server PSUs are now at maximum efficiency (+/- 3%) between 30 and 95% load.For example:
http://www.supermicro.com/products/powersupply/80P...">http://www.supermicro.com/products/powersupply/80P...
And the reason why our quads are using 1000W PSUs (not 1200) is indeed that you need some headroom. We do not test the server with all DIMM slots filled and you also need to take in account that you need a lot more power when starting up.