|Zotac H55ITX-C-E Mini-ITX WiFi Motherboard|
|Reviews - Featured Reviews: Motherboards|
|Written by Servando Silva|
|Wednesday, 13 October 2010|
Page 7 of 17
Zotac H55ITX-C-E Overclocking
Now that we've explored the BIOS let's get started with some basic overclocking. Last time I tested the H55N-USB3 to check max BCLK frequency, and then I moved to CPU overclocking. This time, I really wanted to do the same, but all my efforts were useless. I took my trusty Intel Core i5 655K CPU and installed it in the Zotac H55ITX-C-E. That way, I was already sure CPU wouldn't be a limiting, and since I'm using a pair of G.Skill ECOs DIMMs, all I needed to test was the motherboard itself. Here's a screenshot with the CPU at stock settings with Hyper Threading and Speedstep enabled.
Intel Core i5 655K at stock frequencies with Speedstep enabled.
The reason I said my efforts were useless is because it seems I found a wall when overclocking at 175-180 BCLK frequency. It wasn't that bad, because I could reach a completely stable setup running at 3.8GHz with stock CPU vCore. However, I wasn't able to try higher frequencies with higher voltages because of the BCLK limiting. After that, I decided to use the magic unlocked multiplier to try some higher frequencies but, guess what? It seems this BIOS wasn't done to work with unlocked processors (even if Zotac says so in their homepage). The Core i5 655K comes with a 24x multiplier, which can be easily raised to more than 40x values. However, while I was able to increase it to 26x, every time I tried higher values, the motherboard would post at 24x (default). So, that's where my adventure ends, because I wasn't able to pass 3.8GHz with the unlocked multiplier. Perhaps, a newer BIOS version could fix this up.
Intel Core i5 655K running fully stable at 3.8GHz with stock heatsink. This was our best result with the H55ITX-C-E.
My second hypothesis was that it wasn't a BCLK limiting, but more of a processor limiting. Not because it couldn't reach BCLKs or because it was a very bad sample, because I've tested it before and it did excellent, especially on air-cooling conditions. Somewhere, I had heard about Zotac having issues with Clarkdale CPUs regarding iGPU frequency. I'll easily confirm this later when 3D tests get done.