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发表于 2012-8-5 16:08:15
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本帖最后由 cuda 于 2012-8-5 16:17 编辑
內存老外試過了, 好像1%可以減少15秒. 但1600CL8有些難找, 因為主板是要用 1.5V 的內存.
另用你的加速大法, 8102 現在跑10分10秒左右, PPD 有 52萬. 8101 12分40秒, PPD 有37萬. 機器跑得十分穩定.
ocw 发表于 2012-8-5 15:27 
祝贺o版，推土机的真实实力发挥出来了，其中8102跑10分10秒PPD应该有53.5万。另请问目前推土机使用的是什么电源？
关于内存，据说直接买低延迟的高价内存可能都没有用，因为服务器主板一般很保守，仍然会按高延迟标准来跑。最近看到一篇文章说有两种方法可以提高服务器主板的内存性能，一种是刷G34 OC BIOS(仅适用超微4路G34主板)激活内存的XMP profile；另一种就是刷SPD，适合一般主板。
详见：
Each memory module can have up to 3 different sets of timing programmed into its SPD (internal memory.) I'll touch on these separately.
Every module has a "base" value, usually referred to as the "SPD timings" or the "JEDEC timings". These are intended to be fail-safe timings. Most memory modules I have seen have the JEDEC DDR3-1333H standard specifications programmed into their SPD, which is in part the 9-9-9-24 timings and 666/1333 (DDR) speed you see by default. JEDEC is just an organization that issues standards for various thing, kind of like ANSI. If you are interested, google them. For the purpose of this conversation, all you need to know is that every memory module has some set of specs programmed into it, and usually the specs are a lower JEDEC standard.
Each memory module can also have up to 2 XMP profiles programmed into them. These are normally the more aggressive speed and timings that you see advertised when buying memory - in your case, the 7-7-7-21 is part of an XMP profile for those modules.
Memory with an XMP profile assumes you are going to use the memory in a motherboard that can use the XMP values. Most desktop MBs do give you an option to load an XMP profile for your memory. If you install such memory and just boot up the system without going into the bios to load the XMP values, your memory will run at the lower JEDEC specs. Once you do load the XMP values in the bios, you will see the XMP speeds and timings for your memory.
That brings us to our current situation - we are running memory intended for performance desktop motherboards in server motherboards. Server board assume you are not going to "tweak" anything in the system (or at least very little), sacrificing performance for stability. Because of this, we have no way to load an XMP profile in the bios like you traditionally would in a desktop system. When you boot up a server like this, the memory will use its default JEDEC specs, which is exactly what you are seeing and what I would expect.
So, given all of this, how do we run memory at XMP timings n a server board? There are basically two options - flash the SPDs on your memory with the XMP values, or use tear's O/C bios for SuperMicro 4p motherboards. Since you are talking about a board that is not a SM 4p, you are left with only one option - flashing the SPD on your memory.
Flashing the SPDs on memory modules is not that difficult to do. There are commercially available tools to do it in Windows (Thiaphoon Burner is one of them), or there is the open source eeprog available in Linux. Our friend tear has also written a utility to make the process much easier in Linux using eeprog. There is no documentation on this tool yet, as there hasn't been that much demand for it. In a nutshell, what you do is overwrite the "base values" (normally the JEDEC values described above) on your memory module SPDs with a more aggressive set of specifications. What we normally do is use the specs from the memory module's XMP profile - this is actually what tear's utility does. The thought is that if the memory module is "rated" for the XMP specs, then flashing these specs to be the default should be safe.
If/when you are ready to do this, please log into our IRC channel - search the forum for the server/channel. It will be MUCH easier to walk you through it real-time than for me to try to write instructions for you. |
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发表于 2012-8-2 15:00:55
发表于 2012-8-5 15:27:06