SSD Performance
Ken in Regina
I just installed a Samsung 840 EVO SSD in my main computer to replace the boot drive. Samsung provides some very useful software with the drive. It includes a Data Migration app that is basically drive cloning software to make it simple to clone your existing boot drive onto the new SSD.

It also includes a tuning app (Samsung Magician) that lets you set up your SSD for max. performance, max. reliability, or max. capacity. You can run a set of benchmarks after making setup changes to see what the results are. Turns out that in my case there isn't really much difference between the three different setups. The max. capacity setting allows an additional 7GB of capacity over the other two settings so I may use that setting.

However, there are a couple of other useful bits of information the Magician tells you that can make a big difference in performance. First, it tells you if you are using a SATA interface that gives the best performance. In my case the answer is No. My motherboard only has SATA 2 which is maximum 3 GB/s transfer speed. The new SSD will give its best performance when attached to a SATA 3 controller (6 GB/s). I get such a huge performance increase with the SSD over the old hard drive that I'm not sure I care to spend the money on a SATA 3 interface card.

The other bit of information was something I could do something about for free. My motherboard BIOS settings default the SATA controller to IDE mode rather than AHCI mode. Most newer SATA hard drives and especially SSDs will perform best if the controller is set to AHCI mode. I don't have any IDE drives in this system so I changed the BIOS setting. It made a significant difference in performance. The sequential read and write benchmarks improved by 10%-15%. The random read performance was quadrupled and the random write performance doubled!!

For the record I need to warn anyone thinking about making this change that if you don't do it right you can cause your computer to not boot. It requires a change in the Windows Registry *before* making the change to the BIOS setting. If you don't make the registry changes, or don't make them correctly, Windows will not recognize the boot drive and won't be able to boot.

If you are comfortable doing such things and have all SATA drives in your computer and your computer is not set to AHCI mode in the BIOS and you want to tinker, here's a link with the details.


Standard Disclaimer: If you have to ask questions like "What's IDE mode?" or "What's SATA?" or "How do I edit the Registry?" and your system is currently functioning nicely you might probably just want to ignore all this or you could cause yourself a world of hurt.

Interesting discussion as usual, Ken.

I have converted everything I actively use (Desktop PC, laptop, and Viliv UMPC) to SSD some time ago mostly for better durability (I have never trusted the mechanics of spinning disks being read by moving arms at microscopic clearances), lower operating temperatures, and, to a lesser extent, speed. One qualification: the PC uses a hard disk/SSD hybrid approach to achieve 5 Tb total capacity at a reasonable cost. It seems to work seamlessly and invisibly.

I had not focused on the SATA 2/3 issue until Ken raised it. Maybe I will try to catch up to Ken with some exploratory reading. But otherwise, I am an SSD man for sure.
Ken in Regina
Hey SpadesFlush,

This was a bit of a drive shuffle. I already had an SSD in my main tower and in the PC in my shop. I have a third tower that I'm using to test Windows 10. Until now there was nothing pushing me to replace the boot drive with an SSD. It's used mostly as a media server and an occasional test system for stuff I don't want cluttering my other systems.

However, after a few reboots during the Windows 10 installation and more reboots with some of the upgrades and tests I'm doing I found the waiting was really getting annoying. Like you, I'm pretty spoiled. The other two PCs are running SSDs on the boot drives, my "laptop" is a Microsoft Surface Pro with a really fast SSD and my tablet and phone (both Android) are all solid state memory. I'm not used to waiting for a hard drive restart. I rarely booted that box so it wasn't really an issue. Until now!

Last week I found a Samsung 840 EVO online at Future Shop for a good price and free shipping so I made the purchase. The SSD in my main tower is the original Samsung 840 model so I figured I would swap the new 840 EVO into the main tower to get the extra bit of performance and put the existing model 840 into the server/test tower to replace the ancient 200GB boot drive.

Here's where it gets interesting: because of the SATA 2 controller on both motherboards I'm seeing very little performance difference between the two SSDs. The little bit of difference I put down to the fact that the motherboard in the server/test tower doesn't support AHCI and the one in my main tower does. When I enabled AHCI in the main tower the benchmark picked up, as I noted in my original post.

You won't have to read much on SATA 2 vs SATA 3 to understand that particular issue. It's the interface that connects your hard drives. And it's all about throughput.

- SATA 2 ports max out at 3 GB/s (gigaBYTES per second).
- SATA 3 ports max out at 6 GB/s.

If you have a drive that uses SATA 3 and is capable of pushing data at more than 3 GB/s if the bandwidth is there, hooking it up to a SATA 2 port simply throttles the performance. It's a smaller pipe so less gets through it.

(This is the same issue with USB. If you have a device that is USB 3, and it has the performance to actually take advantage of USB 3, hooking it to a USB 2 or USB 1.1 port will choke it horribly.)

The 3 GB/s vs 6 GB/s won't have a huge effect on most conventional hard drives because they can't get the data on and off those spinning platters fast enough. But if you have a good quality SSD like the Samsungs you give up some performance by hooking them to SATA 2. If that's all your motherboard has on it, the only option is to add in a SATA 3 card.

Or build/buy a new system.

I've decided I'm not going to spend the money for a SATA 3 controller for either system. The performance increase of the SSD vs the hard drive it replaced is stunning. The sequential reads and writes are 10 times faster. The random reads and writes are 50 times faster!!

The absolute maximum additional increase I could get by changing the controller to SATA 3 is double. But that's only if the drives could max out the full 6GB/s. That's not reasonable to expect. Not even close. The 6GB/s is a maximum top end for the interface. It's set that high so that high performance devices can run at their peak performance WITHOUT max'ing out the interface.

So I might get 1.5x the current performance with an interface change. Compared to the 10x and 50x that I've already picked up, it's hardly worth the cost and added complexity. It's called the Point of Diminishing Returns. I'm there.

It's a treat to have reboots measured in seconds rather than minutes.

Ken in Cape Breton
We've replace both computers at home, the laptop and the tower, (yea, we only have two computers that are any good...) with ones using SSD for the boot drives. Boot times, from off to up and running and online are in the order of 27 seconds now. Huge improvement over the old machines that were taking multiple minutes to boot up.
I am at peace with my PC's speed both booting and file transfer rates so I think I will leave well enough alone.

One important SSD benefit for me is hardware operating temperatures. My "tower" PC operates so much cooler with the SSD that I decided to remove the (noisy) fan. I now have about 10 months operating experience with this fanless configuration which of course included the summer without adverse consequences except one. When the machine boots, I get an error message that says I am about to go to Hell because there is no fan. While it is a simple override (push F2) I wonder if anyone knows how to suppress this boot hitch...
How about a high value resistor across the fan socket! Which fan are you speaking of? Not the one for cooling the cpu or the one in the power supply I assume.

If your hard drive actually generated heat in a tower, you should have thrown it out! I have never had one more than mildly warm. Now the secondary one in my old laptop...that's a different story. Unfortunately it is too old to support SSD.

Originally Posted by tcassidy
How about a high value resistor across the fan socket! Which fan are you speaking of?...
It is the one at the back that vents into the atmosphere; just kind-of a general exhaust fan like in the kitchen wall.

If your hard drive actually generated heat in a tower, you should have thrown it out! I have never had one more than mildly warm...
I pulled the fan because of the noise it was generating rather than because of HD heat. I have a digital IR thermometer and it showed somewhat lower operating temps on the SSD hybrid than on the straight HD but it was not a deal breaker.
I have a hybrid but don't use it. It was for one of the other laptops and I was unimpressed with its performance. Like Ken, I use SSDs for the main drive and a large secondary standard mechanical drive in my desktops. I am still not sure of SSD reliability so generally stick with Intel ones though. Of course he backs up his drives way more often than me!


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