Topic: Testing: internal storage vs USB flash drive performance

I'm one of those Wii U owners who decided to ignore dire warnings against using a USB flash drive for external storage. Basically, I use a 64GB Sandisk Ultra Fit USB drive (USB 3.0) for my overflow storage. Backlog and other inactive games are moved there to free up space in the system memory. Now, I had been assuming that the system memory — also Flash-based — would be faster because the USB 2.0 ports limit data throughput no matter how fast the drive. Last night, I decided to test my assumption.

I timed how long it took to start Citizens of Earth, running it from the USB flash drive. Then I moved it over to system memory and started it again. To my surprise, startup time did not change: 22-24 seconds. So while there might be that warm fuzzy feeling from knowing I'm saving game data to more reliable memory, there doesn't seem to be any performance advantages compared to running the game straight off the USB drive.

i think the way the game utilises system memory will also be a factor. It's unlikely you'd be streaming much in something like Citizens of Earth. I think a better test would be initial load of the city in Lego City.

Hmm. I'd also like to know if there is a difference in using a plug & play external HDD with external power source vs without.

I've done both and I can't say I've seen any difference in performance. Everyone's experience differs of course, but I wouldn't bother with an externally-powered drive again myself.

I doubt if HDD power source will make much of a difference. A typical USB 3.0 drive — or even my USB 3.0 flash drive — is capable of a faster data transfer rate than the USB 2.0 port on the Wii U can handle. The USB 2.0 port is the limiting factor. That is why I am surprised it's not any faster when loading from system memory. It's certainly loading a bunch stuff, since Citizens of Earth is notorious for its slow loading times and takes 22+ seconds to get started. Of course, my one single test is not exactly very rigorous.

It could be that the Wii U comes with some slow flash memory hardware. Or it could be that beyond a certain speed, other factors apart from raw data read speeds dominate game startup time.

Just out of curiosity I ran a disk benchmark on an SSD, 2.5" HDD and an old thumb drive I have lying around. These are the numbers I got at the point where the performance of each were levelling out.

ThumbDrive: 27MB/s
HDD: 85MB/s
SSD: 550MB/s

For reference:
USB 2.0: 60MB/s
USB 3.0: 400MB/s
100Mbps -> 12MB/s

The flash-memory might be connected to an usb-connection, which means it will never be faster or slower than an external drive.

Yeah I was going to say the bus speed on the memory controller may be the bottleneck there. On the plus side that means you won't feel hard done by running games from an external drive!

To be fair though there's more to how long a game takes to load than just the raw speed. In terms of the media itself things like access times can also play a part. Then there are other bottlenecks like the speed of the CPU and RAM, how long the system takes to actually start to run the program. Especially for smaller titles and especially given that the system shouldn't be reading the entire game into memory before booting.

With all that said, USB 2.0 isn't much of a bottleneck for the average thumb drive, optical drives or even HDDs. But for faster drives like SSDs? It's certainly a bottleneck. Given that a good SSD is easily 5x faster than the average HDD. But again, 5x faster in theory. There are other bottlenecks. Take GTAV on PC for example, HDD vs SSD.... SSDs are clearly faster. But that doesn't mean 5x faster load times. It's closer to just under 2x faster even though on paper it should be 5x. Because of other factors.

In fact, USB 2.0 is a serious bottleneck for today's modern thumb drives, built to run on the much faster USB 3.0 port. The Sandisk Ultra Fit that I use was benchmarked by reviewers on Amazon at 130-150MB/s (sequential reads). That's much faster than USB 2.0's theoretical limit of 60MB/s. A USB 3.0 flash drive plugged in a USB 2.0 port will still work fine, but you'd be getting USB 2.0 speeds, which is about half of the theoretical limit.

@cwong15:
You should have read what I was saying before you replied I think. I did say that USB2.0 isn't much of a bottleneck for the average thumbdrive (~30MB/s), HDD (~85MB/s) or optical drive (~30MB/s). But then I also said that for faster drives and things like SSDs it's certainly a bottleneck. High speed thumbdrives do exist, I never said they didn't.

All I'm saying here is that the worry that USB2.0 is seriously limiting things is a bit overstated. Most people aren't plugging really fast flash media into the back of their Wii Us. Just do the economics of it. A fast USB 3.0 thumb drive is about $1/GB. So you spend something around $60 for a 64GB drive. That same money could get you a 500GB portable HDD. So I think being bottlenecked by USB2.0 on the Wii U is very much a niche case thing.

@skywake: in fact, the 64GB USB 3.0 thumb drive I am using that achieves 130-150MB/s costed only $24: less than half what you estimated. These aren't "high speed" thumb drives any more, they are just ordinary thumb drives. Prices plunge. Technology moves on.

I happen to think this flash drive is viable for my needs. 64B may not seem much, but that is triple the free space in my Wii U and will fit a lot of eShop and VC games. In the unlikely event that I run out of space I can delete games that I am tired of. After all, I can always re-download them. The best part is that it makes my Wii U elegantly solid state — the fan being the only moving part — with just this little bit of plastic protruding a quarter inch from the back (it's really tiny). No Y cables, no external power supply, no extra boxes.

I'm sure a 500MB HD will make sense for some people. It just happens to be overkill for my needs.

@cwong15:
I meant Australian prices, I should have put AUD after it. Looking at a US site for US prices I can see some 750GB HDDs for under $50US. So the point remains. It's kinda hard to justify getting a faster thumb drive when you can get a hell of a lot more storage for just a little bit more. And I suspect most of the people using thumb drives are getting 16GB ones from a bin.