Not long ago, we published an article comparing four very different SSD solutions, all in the same price range. This roundup included controllers from SandForce, JMicron, Marvell, and even a small company called Phison. NAND types varied quite a bit too, from synchronous (on the Crucial M4) to asynchronous (on the OCZ Agility 3) and Toggle (on the Patriot Torqx 2). After all was said and done, we really liked the Crucial M4 for its performance across the widest type of files being used, and the OCZ Agility for giving us Sandforce sheer speed for a good price, even though a lot of performance was sacrificed by using asynchronous flash to reach that price.
Today we are looking at an individual drive, from A-Data. You probably know about A-Data for their low-cost memory and flash solutions. The S511 SSD drive we’re looking at today is priced to be competitive with the likes of the asynrchonous powered SandForce drives such as the OCZ Agility, but providing full-performance ONFI 2 spec synchronous flash.
Sadly for A-Data, you probably wouldn’t realize this by looking at the product information. Most manufacturers provide pure sequential transfer specs, and in those tests, asynchronous flash doesn’t suffer much at all. It’s when you get to transferring many small files where such drives start to fall behind. So just by looking at price and sequential specs, you would probably never realize that the A-Data S511 has more in common with the likes of OCZ’s Vertex 3 drive or Kingston’s HyperX. The big difference is, those drives all hover in the $250 price range, while the S511 sits at $205, right above most of the slower asynchronous drives.
How To Tell Asynchronous vs Synchronous
Unfortunately the standard of declaring asynchronous vs synchronous on product packaging has not been set yet. Right now, the manufacturers simply let the brand and price set them apart. For instance, OCZ Agility 3 is the SandForce asynchronous product, while OCZ Vertex 3 is their SandForce synchronous product. They even have a version that uses Toggle Flash, the Vertex 3 MaxIOPS, which can be even faster, but doesn’t fit into ONFI standards. Even the A-Data S511 we are looking at today has its own asynchronous version – the A-Data S510.
One way to tell is by looking at the part numbers on the chips themselves, but even this doesn’t always tell the whole story. For instance, Micron NAND will tell you in the part number (it’s the last digit) but Intel branded will not – and as we’ll see later, they use almost identical part number layouts. And besides, not everyone has a screwdriver and datasheet handy when shopping for SSDs.
For now, the only way to really tell, if you are unsure, is by Googling it. The folks at the XtremeSystem forums have been maintaining a list, which makes things a bit easier.
With that rant/tidbit out of the way, let’s get on with the rest of the review!