I've been asked a lot about the relative performance of my Adata SD and MMC cards.
Therefore I have put down a small test.
Test #1:
Using Kingston TravelLite USB adapter and a 3,9 GByte test file I am reading the following transfer rates:
150X 4GB SD from computer to card: 8 minutes 3 seconds (8.1MByte pr Second)
150X 4GB SD from card to computer: 7 minutes 13 seconds (9.0MByte pr Second)
200X 4GB MMC from computer to card: 24 minutes 34 seconds (2.6MByte pr Second)
200X 4GB MMC from card to computer: 23 minutes 17 seconds (2.8MByte pr Second)
Test #2:
Using the Builtin SD/MMC slot (MMCPlus compliant) in my laptop and the same 3,9 GByte test file:
150X 4GB SD from computer to card: 8 minutes 21 seconds (7.8MByte pr Second)
150X 4GB SD from card to computer: 7 minutes 52 seconds (8.3MByte pr Second)
200X 4GB MMC from computer to card: 8 minutes 49 seconds (7.4MByte pr Second)
200X 4GB MMC from card to computer: 6 minutes 2 seconds (10.8MByte pr Second)
Test #3:
Using the Axim X51v (fixed to 624MHz), a SanDisk Ultra II CF and a 100MByte test file:
150X 4GB SD from CF to SD: 1 minute 40 seconds (1.00MByte pr Second)
150X 4GB SD from SD to CF: 6 minutes 52 seconds (0.24MByte pr Second)
200X 4GB MMC from CF to MMC: 1 minute 46 seconds (0.94MByte pr Second)
200X 4GB MMC from MMC to CF: 6 minutes 57 seconds (0.24MByte pr Second)
Test #4:
Using the Axim X51v (fixed to 624MHz), a SD/MMC to CF adapter with a 150X SD and a 100MByte test file:
150X 4GB SD from CF adapter to SD: 1 minute 54 seconds (0.88MByte pr Second)
150X 4GB SD from SD to CF adapter: 1 minutes 52 seconds (0.89MByte pr Second)
200X 4GB MMC from CF adapter to MMC: 1 minute 50 seconds (0.91MByte pr Second)
200X 4GB MMC from MMC to CF adapter: 2 minutes 29 seconds (0.67MByte pr Second)
Test #5:
Using the SD/MMC to CF adapter in a Apacer Mega adapter in the computer and a 1GByte test file:
150X 4GB SD from CF adapter to Computer: 3 minutes 14 seconds (5.15MByte pr Second)
150X 4GB SD from Computer to CF adapter: 10 minutes 59 seconds (1.52MByte pr Second)
200X 4GB MMC from CF adapter to Computer: 11 minutes 3 seconds (1.51MByte pr Second)
200X 4GB MMC from Computer to CF adapter: 18 minutes 47 seconds (0.86MByte pr Second)
Test #6:
Using the SD/MMC to CF adapter Apacer Mega adapter in the computer and a 1GByte test file:
2GB SanDisk Ultra II SD from CF adapter in Apacer adapter to Computer: 3 minutes 2 seconds (5.49MByte pr Second)
2GB SanDisk Ultra II SD from Computer to CF adapter in Apacer adapter: 11 minutes 14 seconds (1.48MByte pr Second)
2GB SanDisk Ultra II SD from Apacer adapter to Computer: 1 minute 51 seconds (9.01MByte pr Second)
2GB SanDisk Ultra II SD from Computer to Apacer adapter: 3 minutes 35 seconds (4.65MByte pr Second)
2GB SanDisk Ultra II SD from Kingston TravelLite adapter to Computer: 1 minute 16 seconds (13.16MByte pr Second)
2GB SanDisk Ultra II SD from Computer to Kingston TravelLite Adapter: 2 minutes 29 seconds (6.71MByte pr Second)
Test #7:
Using the the SanDisk Ultra II CF Apacer Mega adapter in the Computer and a 1GByte test file:
8GB Sandisk CF to Computer: 2 minutes 15 seconds (7.41MByte pr Second)
8GB Sandisk Computer to CF: 3 minutes 2 seconds (5.49MByte pr Second)
Explanation:
In test #1 the adapter was not MMCplus compliant
In test #2 the adapter was partly MMCplus compliant (Ekstra pins but only half clockrate)
The test #3 actually tests the SanDisk CF more than it tests the SD/MMC
And test #4 confirms that the write speed of the CF card was the bottleneck
Test #5 to #7 are for cross reference to se differences in the adapters used and their capabilities
Conclusion:
If the card is mainly for the Dell Axim, high performance cards should be SD or MMC
allthough the Axim does not sport the fast and wide interface to use the full potential of the MMCplus standard
the real bandwith limiter looks to be the operating system itself and/or the local card bus in the Axim.
If you have the equipment that can use MMCplus to the full - then the MMC performs a little better than the SD.
If the equipment (like most) is made primarily for SD cards - then the SD cards performs a lot better than the MMC.
It also looks like "high performance" CF cards are having problems keeping pace with the new SD/MMC cards.
Additional:
The Axim X51v is NOT MMCplus compliant in any way I can add (Source - when opening the Axim you can see the missing pinns)
In these tests I have not taken the actual file handling into account - meaning I have only used one big file for each test.
Saying this - we all know that in special PocketPC 2003(SE) but also Window Mobile 5 are both slow when it comes to handling
multible small files.
See
MMC Organization Page 10. This means that the full potential from this type of card only is in a MMCplus adapter with the high clockrate and the ekstra pins. Further reading can be found
in where more details about the standards can be read.
There is also a very nice overview on this
Link1 and
Link2 about theoretically speeds depending on the used bus and adapter
type. In special the last site gives a pretty good picture of the theory, bandwith and compatibility issues. And the site also tells us that SD and MMC are domed to 128GB maximum capacity due to its 28 bit sector address. OMG what are we going to DO!
Will
