With my hardware tested and running well at stock speeds in part 1 and part 2, it's time to try for an overclock.
The Asrock Z97 motherboard detects the G3258 on boot up and prompts you to press the P key to enable 'Pentium Anniversary Boot'. Really this is just some pre-configured settings to get you started overclocking. Pressing P will gives you the following screen with some clock speeds to choose from:
I like big boosts and I can not lie
Obviously, when presented with this screen, you're just going to nail it straight on to the 4.2GHz option and see what happens.
Testing
I fired Prime95 up again with the same 'Small FFTs' torture as in part 2 and monitored temperatures using the Linux command 'sensors'. The temperatures reported were about 20°C hotter than before, but held absolutely solidy at the 60°C mark for two hours:
coretemp-isa-0000 Adapter: ISA adapter Physical id 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 1: +52.0°C (high = +80.0°C, crit = +100.0°C)
+1 hour
coretemp-isa-0000 Adapter: ISA adapter Physical id 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 1: +51.0°C (high = +80.0°C, crit = +100.0°C)
+2 hours
coretemp-isa-0000 Adapter: ISA adapter Physical id 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 0: +60.0°C (high = +80.0°C, crit = +100.0°C) Core 1: +51.0°C (high = +80.0°C, crit = +100.0°C)
No errors or warning were reported during the tests:
[Worker #2 Mar 8 22:03] Worker stopped. [Worker #1 Mar 8 22:03] Torture Test completed 177 tests in 1 hour, 43 minutes - 0 errors, 0 warnings. [Worker #1 Mar 8 22:03] Worker stopped. [Main thread Mar 8 22:03] Execution halted.
Overclocked Benchmark
I benchmarked the new setup at 4.2GHz using the same tools and tests as used in part 1 and part 2.
I ran GeekBench three times to make sure the results were consistent:
| Run | Single-Core Score | Multi-Core Score | Full Results |
|---|---|---|---|
| 1st | 3595 | 6562 | http://browser.primatelabs.com/geekbench3/2054643 |
| 2nd | 3600 | 6567 | http://browser.primatelabs.com/geekbench3/2054658 |
| 3rd | 3591 | 6558 | http://browser.primatelabs.com/geekbench3/2048367 |
Disappointingly the GPU benchmarks with the 4.2GHz 'Pentium Anniversary Boot' configuration came out exactly the same as at stock speeds in part 2, so I wont include them here. I suspect some custom settings tuning may yield better results.
Compared to the benchmark from part 1, my overclocked system is almost three times as fast on single core performance and twice as fast using multiple cores:
| Test | Number of times faster |
|---|---|
| Single-Core Score | 2.8x |
| Multi-Core Score | 2.0x |
Tweaking
The BIOS comes with loads of options for OC tweaking:
Tweak my MIPS harder
The core voltage looks a little high on the pre-configured overclock settings, so I've reduced that slightly, and I need to optimize settings for GPU and RAM, but for now I'm happy with my 4.2GHz clock.
There are some good tutorials out there for OCing this kind of rig. In the future I'll give a this guide a go and post the results here.
