Core i7 - Is High VDimm really a Problem?
by Gary Key on October 8, 2008 12:00 PM EST- Posted in
- Memory
Numerous articles and forum posts have been popping up recently about the potential of high VDimm settings damaging or destroying the upcoming i7 processor series. Will high VDimm cause damage? The answer to that question is not so simple actually. Unfortunately, due to the current NDA status, we cannot go into detail about this subject matter but can provide a general brief on it.
Our answer at this time is Yes and No. It sounds like we are straddling the fence but in actuality the correct answer depends on the available BIOS options, BIOS settings, memory selection, and final voltage settings. Intel’s stance is clear on this subject, run VDimm higher than their 1.50V~1.65V guidelines and you will affect the life span of the processor.
Exactly what the impact to the processor will be is dependent upon several factors. Put simply, if you go crazy with VDimm, let’s say around 2.0V~2.2V without additional tuning, then expect to greatly reduce the processor lifespan to a few weeks or maybe days. We have already witnessed several CPUs being damaged or destroyed at the motherboard partners with high VDimm settings, especially those that ran at 2.0V or higher with base settings. By base settings, we mean configuring an i7/X58 platform in the same manner a typical user now sets up a Penryn/X48 DDR3 platform. The rules have changed completely for Intel, just we cannot discuss the playbook at this time (hey, it is frustrating for us also).
Likewise, we have seen high VCore/VDimm test beds operate without a problem for benchmarking purposes (yet still fail with long-term bench testing) provided a multitude of BIOS settings for the core, DIMM, IMC, Uncore, and QPI selections were properly set. The base secret (there are more) is maintaining correct amplitude levels, something we will discuss at product launch. For now, high VDimm is not necessarily the true problem here, but it is the quickest way to damage/destroy an i7 if the rest of the system is not properly tuned.
However, we highly recommend keeping VDimm at or below Intel’s recommendations along with proper BIOS settings for the long-term health of the i7. Upcoming DDR3 products from the major memory suppliers will all support low voltage DDR3-1066~DDR3-1600 operation with fairly aggressive timings. This is key as the retail 920/940 processors will not be memory multiplier locked. In addition, the vast majority of JDEC spec DDR3 memory currently on the market will operate fine on the X58, albeit at slightly higher memory timings in some cases.
The
extreme performance modules will also operate correctly, as we have
found in testing to date, just at higher timings in order to meet the
voltage guideline requirements. Certain performance modules that
require 1.8V or higher upon POST will probably not work correctly
(POST) unless the board manufacturer steps outside of Intel’s
guidelines. In that case, you can replace the memory, reflash the SPD
if the supplier allows, or toss in a pair of JDEC spec modules (current
1066 is fine), correctly set the voltages and timings that you require
in the BIOS, shutdown, and reboot with the performance modules.
Realize, this does place you outside of the guidelines but most users
that fall in this category are already outside the lines anyway.
Personally, with the right board, cooling, and BIOS settings, 1.7V~1.8V should be fine (no promises yet) and will allow the upcoming low-voltage, high clock speed DDR3 DIMMS to reach the 1866~2200MHz level. This should satisfy most performance enthusiasts, but probably not the extreme clockers who will try for more. For the rest of us, this platform offers simply amazing bandwidth and latency numbers with tri-channel DDR3 1066 or DDR3 1333. In fact, we think tri-channel DDR3-1333 at 5-5-5-12 timings or DDR3-1500~DDR3-1600 6-6-5-15 settings (1.65V) will provide optimal memory bandwidth, write speeds, and latencies for 95% of the 920/940 users at this point. So, unlike the P45/X38/X48 platforms, having low-speed rated DDR3 is not going to be a hindrance to extracting fantastic performance from a i7/X58 setup.
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snakeoil - Saturday, October 11, 2008 - link
nehalem is too expensive processor, too complicated and expensive 8 layers motherboard because triple channel ddr3,3 sticks of too expensive memory,too much problems with memory voltage,too much problem to overclock because automatic overclocking,too high tdp (130 watts even for the 2.6ghz processor,too lousy in gaming.too much problems with quickpath(when are we going to see 4p and 8p nehalems?),too big yields(have you noticed the size of nehalems, this reminds me of gt280 too power hungry), etc,etc,(and you know something, little anand is paid up by intel,you know it ,everyone knows it. etc etcv12v12 - Wednesday, October 15, 2008 - link
Wow... although it's not at all like the P4, the release-speculation, combined with some of the commentary in here and the general hardware and price increase Vs Penryn... it sure is looking like a leap from PIII to early initial P4s on paper. In reality it's just new tech, which always requires an initial and usually expensive surge into.While those of you that have Penryns now... getting a nehalem anytime soon would be foolish and a waste of money, unless you're loaded (lying to yourself) and or running a very competitive, media related business—where gains in CPU productivity are crucial... Playing around (aka OC'ing, which I LOVE) sounds like a futile leap. Just wait for Xbit-labs and the extreme forum top earners to take the plunge for you. They ALWAYS have like 5 guys with more money than Gates—tearing stuff apart, pushing the limits, burning up expensive hardware just to be "that guy." The forum heros WILL take the lead as they always do. Just be patient and wait. There's nothing to fear, unless you've already planned on taking the leap and started parting out old boxes. lol... ciao!
v12v12 - Wednesday, October 15, 2008 - link
Wow... although it's not at all like the P4, the release-speculation, combined with some of the commentary in here and the general hardware and price increase Vs Penryn... it sure is looking like a leap from PIII to early initial P4s on paper. In reality it's just new tech, which always requires an initial and usually expensive surge into.While those of you that have Penryns now... getting a nehalem anytime soon would be foolish and a waste of money, unless you're loaded (lying to yourself) and or running a very competitive, media related business—where gains in CPU productivity are crucial... Playing around (aka OC'ing, which I LOVE) sounds like a futile leap. Just wait for Xbit-labs and the extreme forum top earners to take the plunge for you. They ALWAYS have like 5 guys with more money than Gates—tearing stuff apart, pushing the limits, burning up expensive hardware just to be "that guy." The forum heros WILL take the lead as they always do. Just be patient and wait. There's nothing to fear, unless you've already planned on taking the leap and started parting out old boxes. lol... ciao!
Zebo - Friday, October 10, 2008 - link
More "look what we got" articles and nothing of substance. I know you're privileged site here at AT and enjoy taunting other sites with your access but briefs just wastes your audiences time.tgarland - Thursday, October 9, 2008 - link
see Nehalem News architecture diagram of the new nehalem platform and notice the IMChttp://www.augustinefou.com/2008/10/core-i7-vdimm-...">http://www.augustinefou.com/2008/10/core-i7-vdimm-...
deadrats - Thursday, October 9, 2008 - link
am i the only one that thinks that the upcoming nehalem is a little too much like the P4? i mean think about it:when the P4 was first announced intel promised much higher clock speeds, one of the key promises of nehalem is much higher clock speeds.
when the P4 was first announced intel went on and on about what a great cpu it was for multimedia, audio and video, content creators, one of the key promises of nehalem is what a great cpu for multimedia it will be.
when the P4 was announced and released it could only be coupled with expensive and exotic rdram, memory that needed to be run in matching pair of modules, with the promise of unheard of bandwidth (though sdram was an option for a while and they did move to ddr eventually), the nehalem can only be run with expensive and exotic ddr3 that needs to be run in groups of 3 modules.
sounds a little too much like the P4 to me...
7Enigma - Thursday, October 9, 2008 - link
Fanboy go home. While you are there, learn the difference between want and need.Trying to draw a parallel between a yet unreleased processor that looks promising to a P4 that was a stopgap solution to combat AMD's superior architecture at the time is pretty sad.
deadrats - Saturday, November 1, 2008 - link
looks like i was right, dumbass:http://www.hwbox.gr/showthread.php?t=2700">http://www.hwbox.gr/showthread.php?t=2700
deadrats - Friday, October 10, 2008 - link
fanboy? LOL, you have no idea what you are talking about. if you are implying that i hate everything intel and loyal to amd, nothing could be further from the truth. while it's true that i currently use a phenom 9500, the reason is that it was the cheapest quad core available at the time i bought it.as far as x86 based processors are concerned, i personally think we the general architecture should have been abandoned years ago, and in fact intel originally wanted to move us to the itanium and the ia-64 architecture (microsoft even made a 64 bit windows 2000 for the itanium):
http://en.wikipedia.org/wiki/Itanium">http://en.wikipedia.org/wiki/Itanium
quote: "During development, Intel, HP, and industry analysts predicted that IA-64 would dominate in servers, workstations, and high-end desktops, and eventually supplant RISC and complex instruction set computer (CISC) architectures for all general-purpose applications. Compaq and Silicon Graphics decided to abandon further development of the Alpha and MIPS architectures respectively in favor of migrating to IA-64."
if i am a "fanboy" of any cpu it's the cell processor, which is vastly superior to x86 cpu's.
as for how "promising" the nehalem looks, all i can point to is the numerous preview articles were prototype nehalem have been tested but intel demanded that benchmark results not be released to the general public because they didn't want to scare anyone away from nehalem (intel has claimed that the low benchmark numbers are due to immature drivers and early chipset and processor silicon).
ask yourself this: if the nehalem will be that much faster than current generation penryn based cpu's then why is it that intel is selling a 6 core penryn based cpu with up to 16mb of L3 for use in high end servers?
remember my prediction: nehalem will be at most 20 percent faster than current generation penryn based cpu's and most of that performance will be thanks to the higher clock speeds.
IntelUser2000 - Saturday, October 11, 2008 - link
deadrats: ask yourself this: if the nehalem will be that much faster than current generation penryn based cpu's then why is it that intel is selling a 6 core penryn based cpu with up to 16mb of L3 for use in high end servers?Stupid argument. That's because its a server MP CPU and it takes longer time to validate. You might want to know that the Dunnington replaced Tulsa, which is a Netburst MP on the 65nm Presler core and it was VERY recently replaced.