New 932GB 840 Evo read speeds drop when there is data on the drive.

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Tanquen

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The 840 is not the boot drive. The 830 is and it looks normal if nothing is accessing it at the time. Right now I’ve imaged the 830 to the 840 so its 40% full and the poor reads are in the first 40%. If I delete the partitions on the 840 and format one large partition then I get the same read speeds you see on the last half across the whole drive.

Anyone know what is up?

Just did these and they are booth on this PC right now.

yhro.jpg


qdhd.jpg


Now with Sys Specs:

Motherboard: ASUS P9X79 DELUXE, Intel 3930k 3.2GHz - G.SKILL 64GB (8 x 8GB) DDR3 1600
Video Card: MSI HD7970 - R7970-2PMD3GD5
System Drive: Samsung 512GB 830 Series SSD
Data Drive: Hitachi 4TB
Power Supply: SeaSonic Platinum-1000W
LG Blu-ray/HD DVD-ROM GGC-H20L
2 Dell 30" U3011 on Ergotron HD Dual-Monitor Arm
 
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Tanquen

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System specs now in first post.

I was not sure what to make of the IRSTe driver. I have an Asus with an Intel X79 chipset and the Asus site lists both the Enterprise version and the regular. It looked like the Enterprise version was for servers and extra RAID configurations. The Enterprise version (3.6.0.1086) also looks like there has not been an update in some time. I did see a nice write bump on the 840 Evo when I upgraded to the latest (12.8.0.1016) of the regular IRST driver.

How do you know which one to use and would it matter? You sound like this is a known issue of some kind where only the boot drive has good read speeds. ???
 
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Tanquen

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Just did a new install of Win7 on the 840 and the same thing happens even though it’s the boot drive. The 830 looks good but the reads on the 840 are bad wherever there is data on the drive. :(
 
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Tanquen

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Yes the drive was erased and I did say that I did a new install of Win7. Windows 7 created the partitions and they are properly aligned. The area of poor read performance grows as you add data to the drive. If the drive is 10% full then the first 10% of the benchmark has poor read performance and so on. I think the performance was better when I deleted the partition because I formatted and ran the Samsung Performance Optimization and there was again now data stored on the drive. I forgot to mention that the read speed was bad across the whole drive when I deleted everything and just created one partition as a secondary drive in Windows 7. I then ran the Samsung Performance Optimization and the read speed was like the 830 but a little faster and it was across the whole drive. Then I copied a bunch of large files to it just to test and again the poor read area matches the amount of data on the drive.

I did find that some that have the 840 Evo drives have seen this and think it’s because of the cheaper RAM and the way it begins and ends sections of data. Something about it being forced to read a larger or more sectors that the data its really asking for. I don’t know. I did not remember seeing anything about this in Tom’s review. ???

Really hoping that's not true.
 
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sidamos

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Did you ever solve this? Because I am having the same problem with my 3 month old 1 TB Samsung 840 Evo.

When I copy an older file (with dd), I get 70-170 MB/s. Fresh copy of the same file does 520 MB/s.

hdparm varies 130-420 MB/s, but never the original 520 MB/s.
 
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Tanquen

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You have to make sure you are copying the file to a device that is as fast. It sounds kind of like you are copying the file to a regular disk type hard drive. That being said, sold state drives or SSDs are pretty much a rip off. They load windows and some programs a little faster but for day to day use it’s just not a real speed increase. Open a zip file or copy lots of small files and it’s a joke. You get like 40 or 50MBs or less sometimes. Games don’t load any faster my VMware sessions don’t load any faster and so on. Maybe like movie editing with very large files would be a good use but otherwise just get a fast 2.8TB drive for $120. I think they only really make sense in laptops. Then you can see more of a speed increase. If your laptop has a typically slow low power 2.5” 4200 RPM drive, then an SSD can be a great upgrade.
 
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sidamos

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Yes, SATA3 and AHCI.

I copied the file to /dev/null, so no physical destination.

Also, performance is better when the PC was off before. Then, the longer it is on, the slower the SSD gets.

My other (new) 840 Evo 500 GB does not show this behavior, so I guess the 1 TB has a defect.

I will return them both. Have ordered a SanDisk now.
 
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gino074

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Does anyone has a follow up to this? I have 2 SSD 840 EVO, one 500GB and one 1TB and both have the same exact problem, read speed on old files drops over "on" time as low as ~60Mb/sec. New written files instead are as fast as advertised read/write speed ~500Mb/sec and so if I start benchmark with any app.
After a reboot the read speed improves a bit, but not much...
This seems to me a common hardware problem of those cheap SSD...
Anyone with those SSD and an always-on PC may do some read test speed on OLD-written data?
One good test for this is using the good old HDTach v3 program. It will show very well the drop on read speed on disk zones where old data is, using the "long bench" option. It works very well on windows 7 in XP compatibility mode.

This seems to me a serious problem on these disks. I have also a 256 840 PRO which does not have the problem (same PC and all SSD connected to INTEL AHCI ports.
 
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sidamos

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My Evo was not hot (tested with Smart).

As I wrote, I returned the Evos and bought 2 SanDisk Extreme II instead.

Just tested the speed of the 5 month old SanDisk with 5 month old files and it performed as expected: 540 MB/s.
 
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gino074

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Using crystaldiskinfo the temp for both drives is 30 deg celsius. Also, my EVO disks are often idling as the OS in in my 840 PRO.
EDIT: to illustrate, here is a HDTach bitmap of my 500 EVO:
WB2eW1H.png

The last part is the one not already written...

EDIT2: to compare, here is my 840 PRO, same pc, same AHCI Intel ports:
TBwDzhB.png
 
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