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October 21st, 2010, 01:30 PM | #46 |
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It does make for interesting scenarios just to see "what if?" However, as you mention, it is not safe in a real world application to have crazy RAID0 setups. I can't imagine trying to back up your 8 TB setup in case you do get a disk failure...
I think performance can also be tweaked by specifying the speed and latency of the RAM used. From articles I have read, the latency improves performance more than the speed of the RAM. I wonder if this has any effect on the benchmarks since we know the amount of RAM available definitely makes a difference. |
October 21st, 2010, 01:50 PM | #47 | |
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October 21st, 2010, 02:16 PM | #48 |
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Really? I thought a RAID0 gives 2x the speed? The only benchmarks I could compare were from Dieter's_PC and Dieter's_PC_upd. He changed to a RAID0 and his MPEG2-DVD was almost a minute faster from 153s down to 98s.
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October 21st, 2010, 02:17 PM | #49 | |
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Last edited by Peter Chung; October 21st, 2010 at 02:48 PM. |
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October 21st, 2010, 03:34 PM | #50 |
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Peter,
Keep in mind that there is a difference between disk access time and transfer rate. In general creating a raid0 does hardly anything to disk access, it remains approximately the same or slightly faster, but that difference is negligent. What does change is the CPU load, especially with software raids, that increases a bit but again not enough to be worth talking about and - this is where the advantage is - it increases the transfer rate of the data almost linearly. A 2 disk raid0 is nearly twice as fast as a single disk, a three disk raid0 is nearly three times faster than a single disk, etc. Again not in disk access but in transfer rate. A modern day disk can achieve transfer rates of around 100 MB/s, a 2 disk raid0 can achieve almost 200 MB/s but in both cases the disk access will be around 13 ms (based on 7200 RPM disks). One caveat: Do not expect that this linear behavior continues indefinitely. The bandwidth of the PCIe bus will at some point become the bottleneck. On my array (12 disk raid30) I can't get better performance than average 853 MB/s transfer with a disk access of 10.7 ms (Areca based). A single disk comes out with about 100 MB/s transfer and 13.5 ms access and a two disk raid0 comes out with around 180 MB/s and 15.8 ms access (Marvell based). BTW this is all based on the old Samsung F1 disks and the newer F3's are a lot faster. |
October 21st, 2010, 04:57 PM | #51 |
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Please, could you explain the difference between disk access time and transfer rate in terms of Premiere CS5 usage? How are the two relevant in the benchmark testing?
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October 21st, 2010, 05:14 PM | #52 |
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On my current system, I could not get better performance than a 92-second result in the AVI Disk Test portion of PPBM5 with my particular two-disk RAID 0 array. And that is with two 1TB Seagate 7200.12 hard drives. I will re-run the test with one of the drives disabled and the other in regular (JBOD) mode, and check back later.
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October 21st, 2010, 05:45 PM | #53 |
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Peter,
Consider the situation you need to look up a phone number in the phone book or yellow pages. Access time is the time it takes you to get to the relevant page. Even if there were a number of people looking for that same name and number, it would still take them about the same time to get to the correct page in the phone book. That can be called access time. Now consider that you need all the numbers from a business or government agency, all on the same page and this may amount to 20 or more numbers. Whether you are alone (single disk) or with a colleague (2 disk raid0) makes no difference in access time. You both need around the same time to find the required page (access time). But now, once you both found the page you need, things get easy if you are working together (raid0). You can write down the numbers, one doing the even entries, your colleague the uneven ones. That means you get the job done in half the time compared to if you were alone. That is transfer rate. Hope this explains it a bit. Last edited by Harm Millaard; October 21st, 2010 at 06:30 PM. |
October 21st, 2010, 06:05 PM | #54 |
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I just got done retesting my main system with a non-RAID disk, and found that the AVI Disk time in PPBM5 increased by about 40 percent -- from 92 seconds in a 2-disk RAID 0 array to 129 seconds as a single drive.
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October 23rd, 2010, 11:24 PM | #55 | |
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But back to the graphics cards: Although a GT 240 with 1GB of DDR5 memory can suffice for CS5, many such cards include barely adequate coolers. A card with good cooling is strongly recommended for CS5. Unfortunately, the best coolers are usually found on premium cards that the manufacturer claims can be overclocked (or have already been factory overclocked to a significant degree before shipment). |
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October 28th, 2010, 09:55 AM | #56 |
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Was wondering if you guys have any opinions on Mushkin Enhanced Silverline RAM. It's on sale for $175 for DDR3 1333 12GB (3x4GB) after rebate. I couldn't find many reviews on it so I thought I'd ask here.
Link: http://www.newegg.com/Product/Produc...82E16820226096 Thanks |
October 28th, 2010, 03:46 PM | #57 |
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Peter,
I have no experience with them. Looking at the price it sounds attractive, but the 9-9-9-24 timings disappoint me for 1333 memory and that may be the reason for the relatively low price. Had it been 1600 memory with these timings and price, I would have said: "Order two sets for me too. You may get extra rebate". |
October 28th, 2010, 04:28 PM | #58 | |
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October 28th, 2010, 07:55 PM | #59 |
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So what do you think about the Mushkin RAM deal, Randall?
Thanks |
October 28th, 2010, 08:06 PM | #60 | |
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Though the Mushkin kit is not that bad since at least it is rated at 1.5V, and 9-9-9 is at the loose end of the official JEDEC latency standards for 1333-speed DDR3 memory. (Remember, the official JEDEC standard CL range for DDR3-1333 memory is CL7, CL8 or CL9.) Some other inexpensive kits of similar capacity, price and speed require a significantly higher than standard voltage just to work reliably at even the lower JEDEC speeds and looser timings. |
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