DFI X48 LT T2R: Floats like a Butterfly…
by Rajinder Gill on April 28, 2008 4:00 AM EST- Posted in
- Motherboards
Still on our feet (BIOS)
Using AUTO for all sub-timings is generally acceptable until we start pushing for every last MHz of bandwidth and latency. The BIOS defaults are generally tight enough for reasonable performance on 24/7 PCs. We used Memset while running Windows XP to check where the AUTO DRAM timing defaults set the memory parameters. The timings shown by Memset were noted by us and entered manually into the relevant BIOS functions. We then began to tighten these values one at a time, noting the effects of any changes on bandwidth, latency, and stability. For benchmarking, we tend to use Memset once the XP operating system has loaded rather than entering overly tight settings directly in the BIOS. We can then begin to tighten the sub-timings far beyond 24/7 settings.
Additional Setting Ranges:
Ref to Act Delay (TRFC): The range of use for 1GB modules in 2GB setups is anywhere from 20-40 depending on overall memory speed. Lower values are more aggressive and give boosts in Read Bandwidth. For double density (2GB) modules, a higher tRFC range is required. For 4GB of memory running up to 1100 MHz, a value of 42 and above is usually required (54 is more compatible). For 8GB of memory a minimum value of 54 should be used.
MCH ODT Latency: ODT (On Die Termination) is used to match the MCH output impedance to the termination resistance of the RAM. Use of 1-2 is fine in most cases. Even for 4GB overclocking we did not find that more than a setting of 1 was required.
Write to PRE Delay (tWR): Range is from 10-13. For high RAM speed, use 12 and above for stability; for benchmarking 10-12 will be faster. Lower is faster.
Rank Write to Read (tWTR): Range is 9-11. Use 11 for stability and 10 or 9 for benchmarking. Lower is faster.
ACT to ACT Delay (tRRD): Range is 2-5. 3 is a good setting that allows high enough FSBs for most users. Higher numbers result in less memory read performance.
Read to Write Delay (tRDWR): Range is 8-9. 8 is ideal for most users; higher values are slower.
Ranks Write to Write (tWRWR): AUTO
Ranks Read to Read (tRDRD): AUTO
Ranks Write to Read (tWRRD): AUTO
The ranges for all these settings are quite well manipulated by SPD and BIOS. For those wishing to experiment, 4 is the lowest and most aggressive setting. 5-4-5 may work for SuperPi type benching. There is a slight write/copy speed increase with tighter settings, but this is only useful for extracting the last ounce of performance. For stability these are best left on AUTO
Read CAS# Precharge (tRTP): 2-3 works well on this board for most users. 2 is used for benchmarking while 3 and upwards are best for stability.
ALL PRE to Refresh: Range is 4-5. A setting of 4 is fine for most benchmarking, unless shooting high over 500FSB.
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Ephebus - Tuesday, April 29, 2008 - link
I remember a time when I was considering the purchase of a midrange ASUS motherboard with a reasonable set of overclocking options in the BIOS but no PCI-E clock setting, and there was no information on the specifications page or the manual as to how that setting would behave when overclocking. I then wrote to ASUS asking if the PCI-E clock was always locked by the board at 100 or if it would vary according to the CPU clock setting, and was actually told by an ASUS support "technician" to "go read a book on overclocking". I managed to get the info later on a forum from a person who owned the board and was kind enough to check it out for me. And that is, when ASUS support doesn't simply delete your support inquiry.With DFI I've managed to actually have short conversations with the technical support staff in the past, was able to report minor BIOS bugs and see them fixed on the next release, etc., so at least for me it's not just a question of whether a DFI motherboard can reach a few MHz more than an ASUS competitor or not on this or that benchmark, it's also all about the feeling of satisfaction from owning a product made by a company that has this kind of attitude towards users, and that always does their best to meet the needs and wishes of enhusiasts. I'll gladly pay more for a DFI product anytime.
Intelman07 - Monday, April 28, 2008 - link
Is there a reason Anandtech reconmends ~400FSB for quad core, does a lower multiplier and a higher FSB increase performance more in a quad core chip?Rajinder Gill - Monday, April 28, 2008 - link
Hi Intelman07,This applies in relation to the FSB limits of the quad cores only ON THIS board; 400 FSB at a trd running near 5-6 will give you a read delay time of around 13ns. Anything over 420 FSB needs a hike in trd while 440+ you need to be looking twoards a trd of 8 which is a delay of 17ns. The drop in write/copy speed bandwidth by reverting to 400FSB is only 500mbs while reads gain 500mbs running the lower tRD (swings and roundabouts). Now factor the VTT and VMCH requiremnts of the higher FSB and it becomes to click.
For more insight into this, 2 of our articles here will explain the fundammnetals and reasoning a little better.
http://www.anandtech.com/mb/showdoc.aspx?i=3208&am...">http://www.anandtech.com/mb/showdoc.aspx?i=3208&am...
and also logical approach to system tuning using Kris' excellent groundwork.
http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...
Other boards which vcan hit higher FSB's and low tRDs change these rules a little. But for the most part, the truth is that FSB overcloking on the quads and Joe Public - 400FSB really is realistic and attainable with real stability - and this is important to a majority of our readers. Of course, we still use our cascades from time to time and hammer the boards real hard without any of the logic written here applied.
The interetsing part comes as no surprise - yup - this all favors unlocked multiplier processors aka QX9650 and 9770 class, just up the FSB - keep the tRD low and hey presto!
The beauty of this board is that it gets close to that tRD 12.5ns latency time at 400FSB at 1.25VMCH and 8GB of memory with no need for GTL tuning- easy as pie- with performance that you can't swing anywhere else using a 12mb cache quad on this board.
Hope that clears it up a little..
regards
Raja
Bozo Galora - Monday, April 28, 2008 - link
Another great article by AT's best reviewer.I have read somewhere DFI's top X48 board gonna have ICH10R and cost ~$400??
Slash3 - Monday, April 28, 2008 - link
Page 2 states "The expansion slot layout is comprised of three PCI Express x16 slots (two x16 and one x4 slot), and three PCI slots."The board itself has 3 physical PCI-E 16x slots and 1 PCI-E 4x slot though, so the sentence is kind of ambiguous.
takumsawsherman - Monday, April 28, 2008 - link
It's the wicked fast 400Mbps version, rather than 800Mbps. Wouldn't want to advance the field. Nope, let's use the 10 year old ancient variety, rather than the 5 year old less ancient variety.I've got an even better idea... Why not throw in some USB 1.1 ports.
Rob94hawk - Monday, April 28, 2008 - link
I got all excited and then I saw DDR2....Might as well just replace PCIE with AGP while their at it.
Rajinder Gill - Monday, April 28, 2008 - link
Just contacted DFI, they are aiming at retail launch of the DDR3 version on the 20th May..Review sample boards should ship within the next week..
regards
Raja
Rajinder Gill - Monday, April 28, 2008 - link
EDIT: Make that early June for full retail (allowing for shipping time etc)..regards
Raja
Rob94hawk - Wednesday, April 30, 2008 - link
Will be looking forward to it. Thank you.