SSD advice please

@bigtabs
average read for a 7200 hdd is close to 100 mb/s (mine does 103)
I thought ssd's were supposed to be massively faster ?

 

My mobo is an Asus P5QD.

Davros, my old OS drive (Samsung HD501LG) has these results
Average Read: 64.8 MB/s
Access Time: 14.1 ms
Burst rate: 168.5 MB/s

Other specs:
Core2Quad 9650
4 GB DDR2 1066
5 other HDs installed so all my Sata ports are full apart from an eSata on the mainboard and 2 at the back.
470GTX
no overclocks

 

Bandwidth-wise, no. Some SSD are very fast (more than 200MB/s) and that's why SATA 1.5Gbps is now a serious bottleneck for them. However, the most important advantage of a SSD is the very low average latency, which most SSD have about 0.2 ms, while most 7200rpm HDD is on the range of 13 ~ 15ms.

So, supposed that you need to read a 1MB block of continuous data, and the HDD/SSD both have 100MB/s bandwidth, it would take 10 ms to transfer the data, but the HDD takes additional 13 ~ 15 ms on average to move the head to the location, so on average the HDD will need 23 ~ 25 ms. However, since SSD has mechanical parts, it takes 0.2 ms to start reading the data, so it needs 10.2 ms to complete the transfer. So even if the bandwidth of both HDD and SSD is the same, for this case it's still twice as fast on average.

 

It's good how a simple question like "What mobo?" can lead to thinking about things a different way.

There are 2 eSata ports internally on my mobo, one of which can be used normally. I had a look in my case and realised I'd plugged the SSD into that interchangable eSATA port. 'Aha!' I thought, and promptly swapped it round with another drive.

This was the improvement I got, old scores first:

Average Read: 147.5 MB/s --> 187.7 MB/s
Access Time: 0.17 ms --> 0.146 ms
Burst rate: 154.4 MB/s --> 210.4 MB/s

The max read speed is now 206.1 MB/s on this latest run, but at a guess it was only above 200 for maybe 10% of the time.

 

Yup. PCChen's example is the best -- a mechanical drive (or a RAID of them) can see some pretty significant file speeds, but as file sizes get smaller, the effective speed of mechanical drives plummet.

PCChen used a 100mb file as an example, but to push it further: consider a pathological case of 300 one megabyte files. This may not be as far from reality as you think; your OS startup loads a TON of little files (DLL, SYS, EXE, registry tidbits, et al) which demonstrates why OS load times are such a boon for SSD. It's likely that all these little files are not written linearly on the same track and/or adjoining tracks on your mechanical drives, even if your disk is freshly defragged.

To demonstrate this pathological case, let's use your 7.4msec seek time and your max transfer rate of 240Mb/sec to load those files. The result is effectively 3.5 seconds -- of which 2.2 seconds is seek time and 1.25 seconds of read access.

Now, let's get a 'cheap' hypothetical SSD that has 0.2msec seek time and only HALF of your max transfer rate (eg: 120Mb/sec.) The entire operation will take 2.56 seconds -- of which 60msec is seek time and 2.5 seconds of read access.

The 'cheap' SSD comes out almost a third faster than RAID config on good mechanical drives, assuming the best possible speed for those mechanical drives (data stored on the sectors at the outermost tracks of platters, no pathological seeks from innermost to outermost, etc.) The reality will be far different, and far more in the SSD's favor.

 

Suryad, I was playing Crysis on a Raid0 setup right up to the day before I installed it on an SSD, it was on the fastest part of the drives. The difference surprised me. Minimum framerates have improved to the point where it only stutters when I use binocs or a sniper scope for the first time on an area I've not gone anywhere near, and that stutter is far less significant than it was - more like a quarter of a second than 3/4. Loading times between levels at a very conservative estimate have halved - probably more like a third or a quarter.

Hardly a scientific comparison, but it seems to me seek times really do have a big impact, and on more than just OS stuff.

 

Apart from loading times, I doubt there will be much improvement in most games. Just ones that have plenty of streaming, and even more likely ones where you can go whatever direction you choose. I expect the new Elder Scrolls game will love SSDs. Hopefully a review site or two will bench the difference.

I also play a snooker game that has commentators. After taking a shot the game would pause briefly as it located the right commentary to play. Bad design more than likely, but putting it on the SSD fixed it anyway.

I'm going to need more of these things.

 

Just sold my Crucial M4 64GB, not enough capacity.
Back to my slow 2TB Samsung F4 until I source an alternative. The drop in performance hurts!

 

I have a 64Gb for my HTPC, as the data on that drive won't ever grow in size really. For a gaming desktop I doubt I'd get anything less than a 256Gb.

 

Gaming, 256gb
Having trouble seeing how they are related....

 

Not enough for what exactly? Usually it's used for just OS and apps and rest stais on regular HDDs.

Then again I haven't really used later windows versions that much so I wouldn't be surprised if 64G isn't enough for it

 

They don't make the "Sacred Terabyte of SSD Gaming Goodness" yet Davros, and if they did I'd probably have to sell my kids to science to afford one.

 

Why is that an issue ?
I'd sell your kids to science for a 1tb ssd without a second thought

 

I'm sorry, they do make 1Tb SSD, on sale at the moment for $2500! Bargain!

 

Malo's children on sale at the moment for $2500! Bargain!

 

Me Used it exactly as you described (OS and Apps) but had to keep watching the size and uninstalling apps.

Going to save for a higher capacity one, they are beginning to come down in price.

 

I want to copy my windows directory over to my new Intel 320 120GB SSD but im having trouble doing a direct image with Acronis and it won't boot even after using XCOPY with all the required settings and using various manual/automatic means to fix it. It's a '34' error with a few 000s in front.

 

@ Tahir2
no doubt its that winsxs folder why the hell is it so big? I read its there to prevent dll hell but the only applications i have are burnaware free, ms word, paint.net and winrar. and they are never updated how can 4 apps create that many dlls.