Question Unexpected poor CPU performance ?

[cparke]

Recently been experimenting in mining Monero (XMR) and seeing one of my machines is surprisingly underperforming the others in terms of average hash rate. Both are using CPU only for mining, and running 100% for the mining at the Linux command prompt with no GUI services. Connected to the same network via home Wifi from the same room. Seeking some kind of explanation on why I might be seeing these results!

System Specifications:

1) Dell Optiplex 790 Ultra Small Form Factor PC

• Intel Core i3-2120 Processor 3.30GHz (2 Cores, 4 Threads, L1: 128KB, L2: 0.5MB, L3: 3MB)
• 6GB of DDR3 non-ECC Unbuffered RAM (DDR3 1333 MT/s PC3-10600 1.5 volt CAS latency 9)
• Avg. Hash Rate 460 H/s

2) HP Compaq 6005 Small Form Factor PC

• AMD Phenom II X4 B95 Processor 3.00 GHz (4 Core, 4 Threads, L1: 512KB, L2: 2.0MB, L3: 6MB)
• 16GB of DDR3 non-ECC Unbuffered RAM ( DDR3 1066 MT/s PC3-8500 1.5 volt CAS latency 8)
• Avg. Hash Rate 500 H/s

It is the (poor) performance of the HP with the AMD processor that surprises me! This is a straight Quad Core processor, as compared to the Dell with the Intel i3-2120 which is a hyperthreaded Dual Core processor. Furthermore, while the AMD's clock and system memory is slightly slower, it has more L1/L2/L3 cache per core than the Intel's. Overall, with double the number of cores, I was expecting something more like 800 H/s or better from the HP-AMD, but strangely these two machines are performing nearly the same.

I'm wondering if there is some other factor that could explain why these two computers are producing similar results?

 

[JWNoctis]

You are pitching a CPU released in 2009 against a CPU released in 2011, a difference not insignificant in those times. If benchmarks are anything to go by, the 2-series Core i3 is much faster core-on-core. It's not just about core count and frequency.

 

[Viking2121]

Well the Phenom series were meant to go against the Core 2 series, they always lost to even the cheapest i3's most if not all the time. That 2120 has a much faster core, and even multi core.

You may be able to get closer to the i3 performance with an overclock, Should get close to 4ghz, but the power draw wouldn't be worth it, would be better off selling it on marketplace and getting another 2120 for what you are doing.

 

[cparke]

Well the Phenom series were meant to go against the Core 2 series, they always lost to even the cheapest i3's most if not all the time. That 2120 has a much faster core, and even multi core.

You may be able to get closer to the i3 performance with an overclock, Should get close to 4ghz, but the power draw wouldn't be worth it, would be better off selling it on marketplace and getting another 2120 for what you are doing.

Very interesting. No, not looking to overclock or anything like that. Just wanted an opinion from folks who know how to evaluate these things better if the fact that these two processors are performing close to the same makes sense, sounds like it does.

The AMD is performing better, but not by a much, despite having twice as many cores and more L caches. I am quite surprised by this discovery, particularly because in regular daily use, the Intel i3-2120 machine seems to perform very slow at times while the AMD machine has no noticeable delays. Maybe it's an issue with the Intel HD 2000 onboard graphics issue instead? The Dell-Intel is USFF and has no PCI-E slots for an add-on video card, so I'm stuck with the on-board. Though the HP-AMD has never displayed such delay behaviors for me, even when I was using it with the on-board video.

At any rate, the HP-6005 is already using the highest performance compatible processor the motherboard can support (95W) so that's all I can do there, but the Dell-790 can be upgraded to the Intel Core i7-2600S (quad core), which I probably am going to do and see if that improves its performance and general usability.

 

[kerberos_20]

there should be performance bump with overclocking northbridge frequency on phenom

 

[geofelt]

The architectures of your two processors are different.
The instructions per clock will be different depending on the details of your workload.