To facilitate our Core i7/X58 motherboard testing, we have been snapping up retail CPU’s from a variety of outlets in the US and Europe. Since most of the users adopting this platform are opting for a Core i7 920 as their mainstay processor, we have been on a buying spree for this particular model while also dropping some hard earned cash for a couple of the 940 and 965XE retail processors.

I purchased my first 920 over three weeks ago from SCAN UK. This particular CPU is a 3838A batch processor, which I proceeded to test in the Foxconn Bloodrage and EVGA X58 SLI motherboards. It’s the same old story really when it comes to clocking, I scoured the forums, spoke with Gary and Kris (who had a head start on me with this platform) and asked them the lowdown of what to expect in terms of voltage related scaling hoping that I had something at least as good if not better than their retail processors.

Like many others out there, I was hoping for a processor that could clock to 4GHz and beyond at fairly low processor core and VTT voltages. This together with an IMC that could handle triple channel speeds well above 1600MHz, actually, make that 2000MHz. The kind of speeds I’d seen posted on various overclocking forums using the 920 processors had voltages just tolerable enough for 24/7 use. I must also add at this point that some of the testing we do on these boards falls well outside the 24/7 bracket. An ever increasing number of boards are released solely with benchmarking in mind, a growing segment of the industry that seems to be on the fringe of demanding complete segregation from mainstream products due to its specialized needs.

A large part of testing these boards involves running both entry-level and high-end components well out of specification ranges, just to see what a particular board can do if pushed or if it will go up in a ball of smoke, something Gary seems to master at times. This may seem trivial to most of our readership, but it’s an ever growing part of the enthusiast sector and somebody around here has to test it, so in comes my need for decent components, especially processors in this case.

While this processor matched the ‘international average’ for core voltage scaling, I discovered that I had to apply ridiculous levels of VTT/Uncore voltage to get it to boot at anything over 185BCLK. A 3.8GHz clock speed fell with relative ease, but pushing up to 4GHz, well that’s where things became real tricky. This processor seems to stop in its tracks with VTT voltage levels over 1.36V (just outside the warranty maximum by the way) or so, causing both of the motherboards to halt during POST with a C1 error.

Manipulating voltages within the OS using motherboard specific software tools can circumvent this condition to an extent, but the voltage has to be ramped up in small steps. Either way, 4GHz stable on this particular processor is way more hassle than it could ever be worth in a 24/7 system so I am stuck at 3.8GHz. Ok, this seems a bit demanding of me, a free 1.2GHz overclock from stock and I’m nowhere near happy! In fact, at this point I was pretty much convinced that both of the motherboards I was testing were duff, not the CPU, especially when I looked over at some of Gary’s early results on the same boards, as well as results of forum members.

I conferred back with Gary on his results, he’s got three retail 920s in his repertoire (with a fourth on its way) and his results are erratic in this department too. One of his processors needs high levels of Vcore to make 4GHz possible, well in excess of 1.50V, and refuses to POST with Bclk ratios set higher than 200, regardless of VTT/Core voltages. The other two (3837A)are better than mine for IMC VTT scaling and can also handle 6GB triple channel memory at 2000+MHz with a little persuasion. Something I found impossible on my 3838A processor with 3GB of memory let alone 6GB. Also, both of his processors allow for 3.8GHz operation at stock or below stock core voltages with VTT near 1.15V. Both processors allow clock speeds to reach about 4.3GHz on 1.45V of VCore, but VTT required is near 1.425V on air cooling with a 2:8 memory ratio, change the memory ratio to 2:10 for DDR3-2000 and VTT requirements hit 1.50V, which also happens to be the maximum amount his processors will allow before throwing up a C1 code on POST.

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  • Rajinder Gill - Friday, January 23, 2009 - link

    I think Gary meant running the Cas 7 ddr3 2000 kits at Cas 6 1600 as a compromise to overall VTT and VDimm voltages. Personally I have not seen any real gains from running cas below 8 over 1600Mhz memory speeds when in triple channel mode on this platform. Other than Everest reporting a boost, the real world apps seem more than happy, even at cas 9 -1600 actually. Does not mean to say that it'll stop people buying the performance stuff though, just that the variability in the IMC kinda points to compromised overclocking on the lower multiplier CPU's. Reply
  • Doormat - Friday, January 23, 2009 - link

    Do I really need 2000MHz DDR3 RAM or will 1600 do if I only overclock to 3.6Ghz?

    Those are the types of questions I'd like to see answered. If I've got a $750 where should I put my money? A $200 or $250 board? 1333 or 1600 RAM?
    Reply
  • Rajinder Gill - Friday, January 23, 2009 - link

    1600 rated kits are probably the best bet or middle ground for decent overall performance vs cost. Triple channel 1600 speeds are more than enough to keep the i7 saturated with data. Reply
  • Joe Schmoe - Friday, January 23, 2009 - link

    I'm not really sure I got the point of the article. I just glanced at it before bed. If you are saying some chips from the same batch overclock better than others.. that has always been true. The IMC is the culprit this time instead of the cache.

    I think its interesting that the X58 boards all seemed to be about equal.

    Apparently, at around 350 dollars all the vendors start using the 20 cent capacitors instead of the 15 cent ones.


    Reply
  • Rajinder Gill - Friday, January 23, 2009 - link

    If you look around the forums, you'll soon realize there are many people that don't or did not know, that's who the article is for really. Its actually on of the reasons I think the overclocking section should now be segregated on site from the mainstream stuff; different needs and different overall goals. Just that you have to appreciate that some are learning while others are already experienced. Reply
  • corporategoon - Thursday, January 22, 2009 - link

    Every article I've read on AnandTech lately that hasn't been written by Anand himself has been absolutely riddled with sentence fragments.

    Did you guys stop proof-reading your articles, or something? It's starting to make my brain hurt.
    Reply
  • vacant78 - Thursday, January 22, 2009 - link

    On top of that, abbreviations jump from almost every sentence with almost none being explained (VTT, IMC,???). What happened to understendable communication? That article almost asks for a warning: "For computer journalists and tech gurus only". Shame. Reply
  • JarredWalton - Thursday, January 22, 2009 - link

    Not all articles go through the full editing process (re: me), so there are grammatical and spelling errors on occasion. Some times it's a question of timing: wait for additional editing, or just post something we feel our readers would like to hear. Reply
  • DigitalFreak - Thursday, January 22, 2009 - link

    I think they let the guys at DailyTech do article proofreading. :0/ Reply
  • The0ne - Thursday, January 22, 2009 - link

    After reading the article I would had to assume that most enthusiast at these technical levels would already have realize that manufacturing of the different parts would vary from batch to batch and sometimes within the batch itself. Having said this I'm not entirely sure if an article needs to be done about this subject if this is a known issue. I certainly expect the variances and would never expect to achieve the same result as another user.

    This applies to both the technical side of each of the parts and the manufacturing of them.
    Reply

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