Overclocking

If all you're after is a stable stock HTPC build, then you're probably better off ignoring this section of the article and skipping over to the performance results or conclusion. Differences between boards are generally small and only manifest under conditions that are either unnecessary or unlikely in an everyday PC build.

Out of the eight boards we've tested in this two-part series, three boards stand out as the most consistent performers for overclocking given a range of peripherals and operating parameters. Spearheading the charge is Gigabyte's H55M-USB3; memory clocking is its main strength, delivering class leading memory speeds on the H55 chipset with 8GB of RAM in place (with or without the IGP active).


Gigabyte's H55M-USB3 is a "Jack of all trades" when it comes to overclocking.

The other two contenders are ASUS' P7H55D-M EVO and ASRock's H55M Pro. Both come a close second with 8GB, while ASRock's H55M-Pro pips the ASUS and Gigabyte boards to the post by a few MHz with 4GB of memory and a high QPI multiplier ratio. At higher BCLKs the Gigabyte board seems to be the best overall bet, handling all of our memory kits in a resolute manner.

IGP clocking—Oops!

One area we goofed up on in part one was our report of IGP related overclocking. Our mistake was believing that IGP frequency remained static while we increased BCLK; this was fueled by the frequency we'd set in the BIOS and also by the fact that there are no operating system tools that report the true IGP clock frequency correctly. Anyway, cutting to the chase, Massman from MADSHRIMPS released an article shortly after our first piece highlighting our error.

As soon as that article was posted, I slapped myself on the forehead for missing the glaring obvious. The tell-tale signs were all there: IGP voltage needed to be increased in tandem with BCLK, reflecting a hike in operating frequency. Further, Intel have never been known to embrace completely free-ranging asynchronous bus architectures, which is exactly what would be needed to maintain a static IGP frequency vs. adjustable clock frequencies of related domains. Such topologies overcomplicate chipsets and usually carry a latency penalty, thus degrading system performance.

Unfortunately, board vendors have not included any kind of corrective algorithm in current BIOS releases to show true IGP operating frequency as the BCLK changes. Despite the Chinese New year break we managed to ask ASUS about this, and they've confirmed a BCLK to IGP clock multiplier relationship and told us that the formula shown in the MADHRIMPS article is "very close" to determining true IGP operating frequency.

What this all adds up to is that processor and memory overclocking is not really hindered much by an active IGP at all—provided you can offset the IGP clock multiplier to keep its bus frequency within bounds. While we wait for vendors to get BIOS releases up to scratch, we've put together a simple Excel-based calculator based upon Massman's findings that allows you to work things out with minimal fuss—download it here.

Out of all the boards we've tested, Gigabyte's H55M-USB3 comes out on top with 8GB of memory in place while the IGP is active. The CPU-Z screenshot posted above at 200BCLK and DDR3-1600MHz holds true with an active IGP. Boards from ASUS and ASRock come a close second, hampered only by an inability to overclock memory as well as the Gigabyte board. The only lemon when it comes to IGP overclocking is the ECS H55H-V1, because you can't change IGP frequency at all on the current BIOS release.

Interestingly enough, ASUS seems to have hit on a performance register or two behind the scenes and deliver slightly better clock for clock IGP performance in the older Futuremark 3D benchmarks. In the real world though, the Clarkdale IGP is best suited for video playback (HTPC) use; you're not going to get a blistering "high-definition" gaming experience, even with elevated IGP clock frequencies and clock for clock performance enhancements.

BIOSTAR TH55XE Test Setup and Power
Comments Locked

56 Comments

View All Comments

  • Swivelguy2 - Monday, February 22, 2010 - link

    Okay, USB 2 transfers a gigbyte in 36 seconds. This is consistent with the rated spec of 480 Mbit/s. Isn't USB 3 supposed to be 10x faster? What's causing the limitation? Is it the implementation by Asus and Gigabyte (like attaching the USB 3 to too narrow of a PCI-e lane)? Is it simply the write speed limitation of the USB HDD used? If the latter, why not write to some flash memory to see if the results improve?

    C'mon Anandtech, I know you can do this right - if you're going to benchmark and discuss the USB 3 capabilities of these boards, do that!
  • Rajinder Gill - Monday, February 22, 2010 - link

    Good point. In-depth analysis of USB 3 & external HDD's etc will be offered up in a dedicated article.

    later
    Raja
  • JarredWalton - Monday, February 22, 2010 - link

    USB devices have always had some level of overhead compared to SATA devices. USB 1.1 devices never actually achieved 12Mb/s but were closer to around 8Mb/s (1MB/s) maximum. USB 2.0 is rated at 480Mbits, which translates into 57.22 MiB/s (remember that Windows uses 2^20 MiB for transfer rates instead of 10^6 MB). However, there's overhead and the maximum sustainable transfer rates on USB 2.0 tend to be closer to ~38MiB/s. At that speed, most conventional HDDs can easily saturate USB 2.0, but they're not significantly faster (i.e the fastest HDD is going to be in the realm of 100 MiB/s).

    Move to USB 3.0 and the maximum theoretical data rate is 572 MiB/s, but there's still overhead that limits performance to 4 Gb/s instead of 4.8Gb/s, and it looks like transfer rates of up to ~380MiB/s will be considered "ideal". Even the fastest SSDs aren't going to come close to 380 MiB/s right now, as they would need external enclosures and SSDs with SATA6G support.

    With USB 3.0, a 1TB HDD transferring data at around 93MB/s is very close to the speed of a 1TB drive connected via SATA, so the HDD is now the bottleneck for USB 3.0. If Raja tested with a fast SSD, we could see if USB 3.0 can get up to ~250 MB/s, but we can't test if it can achieve any better than ~43% of the theoretical throughput without SATA 6G.
  • Swivelguy2 - Wednesday, February 24, 2010 - link

    I'm sure we can come up with a way to challenge USB 3 and make sure the boards are actually performing to the spec. There are two USB 3 ports on the motherboard, how about writing large files to SSDs attached to each one? How about copying a file from one to the other? How about streaming off of a USB 3 camera or two?
  • michal1980 - Monday, February 22, 2010 - link

    Firstly, thanks for ripping into these compaines.

    Secondly; Any plans on testing any of the itx boards coming out? Zotac?

    Thridly. How come reference intel boards are never tested? It would be nice to see how intel mobo's are right out of the gate.
  • Rajinder Gill - Monday, February 22, 2010 - link

    Hi,

    1) Couple of ITX reviews are in the pipeline - including the Zotac H55 and Intel M-ITX 'Jet Geyser'. The Intel review is what I'm working on right now (board is due for release mid-march with an MSRP circa $125)

    2) We've currently got 3 Intel boards in lab due to be reviewed. The Intel 'Jet Geyser' is first. The two other boards in-lab from Intel are the P55 M-ATX and ATX models, reviews for both should be up sometime in March..

    Hope this helps..

    -Raja
  • The Wasp - Tuesday, February 23, 2010 - link

    Raja,

    Any chance you'll be reviewing the new ECS H55H-I ITX motherboard?

    How about the Giada MI-H55?

    I'm trying to pick the best 1156 ITX motherboard, so it would be great to get some more in-depth info on all of the options.

    Thanks!
    Jon
  • Rajinder Gill - Tuesday, February 23, 2010 - link

    Hi Jon,

    We're focusing on the Intel and Zotac M-ITX boards at present,so it will be a few weeks before we can look at the models you mention (will def try and add them in if possible somewhere down the line).

    regards
    Raja

  • The Wasp - Thursday, February 25, 2010 - link

    Hello again,

    I don't know if it's available, but if you could include the Jetway NC97 that would be awesome too!

    Jon
  • grazapin - Monday, February 22, 2010 - link

    Based on past experience, how do you expect the Intel boards to compare to the other manufacturers?

    Strange that Intel is only using the H57 in the Mini-ITX board and not in the larger two. Seems counterintuitive, like in many cases aren't you more likely to want the RAID features in a larger case that can hold more drives, therefore accommodating a larger motherboard also? Maybe that's just my preference or assumption.

Log in

Don't have an account? Sign up now