A matter of performance

While doing a review of a Sandisk microSDHC card (expect the review soon) I had to test several cards using both a card reader and inserted into phones, connected via USB. The performance numbers that the benchmarks produced were kind of disappointing, but not unexpected. I’m specifically talking about the speed at which data is passed through the USB connection and written on internal media via either internal memory (Like N81 8GB) and card slot (like N76). So I decided to closely investigate how the Nseries perform when it comes to reading and writing from their swappable or internal media. Now I must admit I have no idea at what speed data is written onto the memory card or internal memory as Nokia has never published these numbers. But what I do know is that USB 1.0 Low-Speed has a data rate of 1.5 MB/s and Full-speed at 12 MB/s. Now the much faster USB 2.0, now called Hi-Speed USB, has a whopping data rate of 480 MB/s.  But what we do have to remember is that the effective speed is mostly determined by the USB connection, the card or internal memory itself (the speed at which it can be read from and written to) and the speed at which the phone itself reads and writes from and to the memory card. The most important thing to remember is that the entire data chain is as fast as the lowest denominator. In other words no matter how fast USB 2.0 can be, if the other variables are slower it will make the entire process of data transfer slow. With that in mind let’s see how some of these Nseries perform. In this case I’m using the N76 and N81 8GB and we will directly compare them using a dedicated card reader: the Sandisk microSDHC

Test system: HP DV6500 notebook with a 2.0 GHz Intel Core 2 Duo T7300 processor,  2GB of DDR2 RAM, Nvidia GeForce 8400M video card, 200 GB 4200RPM Serial ATA hard drive with USB 2.0 ports and Vista Home Premium.

Test Devices:

-Nokia N81 8GB (Data transfer mode)

-Nokia N76 (Data transfer mode, using Sandisk 4GB microSDHC )

-Sandisk 4GB microSDHC

-Sandisk MicroMate card reader.

Benchmarks used:

-SiSoftware Sandra’s Removable Storage module

-HD Tach (Read speed)

-MP3 Copy Test (619MB worth of MP3 files copied to device)

SiSoft Sandra

The first benchmark used was SiSoft Sandra’s Removable Storage module. The results are in KB/s. It does have a “Mobile Device Transfer” benchmark, but this is only compatible with Windows Mobile devices. First thing that’s clear with these results is that the read and write performance drops as the file sizes get smaller. Second thing that’s very obvious is that a card reader leaves both the N76 and N81 8GB far beyond in performs. The slow performance overall is clearly due to the sluggish performing Nseries devices as the Sandisk MicroMate card reader and the N76 used the same Sandisk 4GB microSD. Third thing that stood out was that N76 and N81 8GB performed almost identical. But as I said before there are three main variables: the USB connection, the card or internal memory and the speed at which the phone itself reads and writes from and to the memory card. So I decided to use the slower 1GB Nokia microSD card included with N76 to try to see if the performance would drop. The slower Nokia card performed exactly like the faster Sandisk’s 4GB microSDHC card. This means that the N76’s USB connections or the way it writes or reads from the memory card is limiting the cards performance.

HD Tach

HD Tach is a low level hardware benchmark for random access read/write storage (In this case only read, as I only had the trial version) devices such as hard drives, removable drives (ZIP/JAZZ), flash devices, and RAID arrays. HD Tach uses custom device drivers and other low level Windows interfaces to bypass as many layers of software as possible and get as close to the physical performance of the device possible. The results are in MB/s. From the HD Tach Benchmark numbers it’s again quite clear  that both N81 8GB and N76 produce similar numbers. The unusual part is that the N76 and the Sandisk card reader are using the same 4GB microSD card, yet the N76 only manages 0.8MB/s while the card reader squeezes almost 11MB/s out of it. This could only mean that the N76 and possibly the N81 8GB are limiting their performance through either a slow USB 2.0 interface or via a slow system that reads/writes to and from their storage mediums. I was also curious as to how the cards included in the standard packages would perform. The 1GB Nokia branded microSD performs quite admirably for a free card scoring 8.5MB/s in HD Tach. While the included Nokia card is nowhere near slow, an upgraded 4 GB Sandisk microSD card performs faster. The higher rated 6 and 8 GB microSD cards from Sandisk have a higher minimum read speed so these should perform faster when compared to the 4GB version.

MP3 copy test

The last test consisted of copying 619MB worth of MP3 files from the test system to the memory card using the Sandisk MobileMate card reader. The 4GB Sandisk microSDHC took 2min 17 sec and the 1GB Nokia branded vanilla card took about 3min 28 sec. Because these tests were performed using the card reader we are sure these are the pretty close to the max we can get out of them. . The Nokia N76 using the 4GB Sandisk microSDHC took a slow 12min 7 seconds to complete the task while the vanilla Nokia card took 12min 28 seconds. Again, this test indicates that Nokia’s Nseries have a bottleneck limiting the card’s performance.

Conclusion

Based on these simple tests we can come to several conclusions:

-In current generation Nseries, no matter if the device is using internal memory (N81 8GB) or card slot (N76) they perform very similar.

-A dedicated USB 2.0 card reader outperforms current Nseries devices by a large margin when it comes to USB data performance.

-Current Nseries devices have a bottleneck that is limiting the performance of high-speed cards: The same 4GB Sandisk microUSB card scored: 0.8MB/s in the N76, while the card reader managed to squeeze almost 11MB/s out of the same card!

I also did a little searching and came across this N91 review done by Mobile-Review. If you remember the N91 has a true built-in hard drive of 4GB, unlike the N81 8GB which uses flash memory, possibly just a card attached on the inside. The N91 uses a Hitachi Microdrive 3K4-4 which has a Sustained Data Rate – 4.3-7.2 MB/s, which indicates that they do have the knowledge to create a device with a decent 4+MB/s throughput, but why are current devices performing so slow?

Comments

[82guy]

Thanks for this. I recently purchased an N82 to replace both my old phone and my broken music player. Having never owned a smart phone before, I didn't know what to expect performance wise, and am at the moment testing the hell out of it, hopefully to conclude that nothing is wrong, well within the DOA period. What especially puzzled me is how insanely long it takes to transfer music. A couple of gigs took the better part of an hour, and I wondered if something was wrong. Well, if something's wrong can still be debated, but at least now I know it's supposed to be that way, and I can live with it. :P Guess I'll be buying a card reader, then.

[Idetrorce]

very interesting, but I don't agree with you
Idetrorce

[Serg]

thx for the review!
im gonna buy n81, but with 8GB card separately
so that i can copy all of my music there and use the same card next time i get a different phone

[N95-1]

i totally agree with your findings, and am wondering how nokia can get away with such a crappy performance in its top-level devices. thats totally disappointing - especially if compared to other high-priced devices like the iphone.