The Transcend 8GB 266X CompactFlash Card is not on the compatibility list. I understand that all CFs should be compatible, but sometimes faster devices cause lot of electrical noise and become unreliable. Did anyone try this CF with their x51v? Thanks.
The Transcend 8GB 266X CompactFlash Card is not on the compatibility list. I understand that all CFs should be compatible, but sometimes faster devices cause lot of electrical noise and become unreliable. Did anyone try this CF with their x51v? Thanks.
Please excuse my ignorance. What do you mean by electrical noise?
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Please excuse my ignorance. What do you mean by electrical noise?
As CMOS devices switch, they cause momentary high current draw on their power supplies, due to the fact that both transistors are momentarily on, de-facto shorting the power supply to ground. Secondarily, there is a higher current draw as the outputs drive the capacitance of the circuit traces and the inputs of the sink devices they drive into cause momentary current draw, until the level stabilizes. As there are many outputs switching almost randomly, especially when various delays due to impedances of lines become significant with respect to the clock frequencies, these spikes on the power supplies become basically a random noise. This noise is largely filtered by the decoupling capacitors, but as the devices become faster, the spikes can be of higher magnitude and shorter duration, so the decoupling capacitors will not be as effective cleaning this higher frequency/amplitude "noise". Since the noise is seen by the reference circuits of the receiving device, it then can either see erroneous input levels of signals or clocks and therefore the computer can behave erratically or even stop working, depending on the design tolerance, power supply or battery levels, temperature and the speed and noise tolerance of the receiving device, e.g. CPU, which would, for example, clock in the wrong data from the memory. This can happen when older technology platform gets new companion components and why I had the original question.
You are right, it shouldn't. Unfortunately (or fortunately) I make my living fixing things that should work, and so do millions of engineers. Anyway, I ordered one and will report on it.
As CMOS devices switch, they cause momentary high current draw on their power supplies, due to the fact that both transistors are momentarily on, de-facto shorting the power supply to ground. Secondarily, there is a higher current draw as the outputs drive the capacitance of the circuit traces and the inputs of the sink devices they drive into cause momentary current draw, until the level stabilizes. As there are many outputs switching almost randomly, especially when various delays due to impedances of lines become significant with respect to the clock frequencies, these spikes on the power supplies become basically a random noise. This noise is largely filtered by the decoupling capacitors, but as the devices become faster, the spikes can be of higher magnitude and shorter duration, so the decoupling capacitors will not be as effective cleaning this higher frequency/amplitude "noise". Since the noise is seen by the reference circuits of the receiving device, it then can either see erroneous input levels of signals or clocks and therefore the computer can behave erratically or even stop working, depending on the design tolerance, power supply or battery levels, temperature and the speed and noise tolerance of the receiving device, e.g. CPU, which would, for example, clock in the wrong data from the memory. This can happen when older technology platform gets new companion components and why I had the original question.
You and Menneisyys should have lunch together. :approve:
Funny thing is I was also planning. To buy the a 8GB 266X CF card from A-Data. Guess I better wait until somebody else buy's it first.
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Let me know how that card works... I'm in the market for another high capacity CF card cause my 8gb microdrive just crapped out on me.
I ordered mine from Compuplus for $101 plus shipping. I'll let you know how it works out. If it is otherwise compatible, it should be much faster and dependable than any microdrive. Those are mainly good for capacity, but the flash memories catche up in couple of years, just about when the drives wear out, like iPod mini...
5/18/07 The CF got here in a day and a half (from NY to Califirnia). I did a quick test, including playing some video and audio files, all is good and smooth. I'd certainly recommend the card as well as Comp-u-plus.
As far as preliminary performance is concerned (most likely effect of both memory speed and bus width), Sprite backup of 52.53MB to the 266 MHz 8GB CF took 2.1 min, the exact same backup to 150MHz 4 GB Trascendent SD took 5.15 min.
how long does it take you to transfer files from your pc to cf card?
ie. 100mb in 1min =1.66megabYtes per second. (my Cf card)
I am assuming that you are asking about transfer from PC to the Axim over USB. The Axim x51v uses one of the old USB specs, so the transfer speed to any memory is very slow. I don't use the Axim to transfer large data files (e.g. multimedia or maps) to any of the cards (it may take hours), I use USB 2.0 interfaced card reader. The USB 2.0=480Mbps, USB 1.1=12Mbps, and USB 1.0=1.5Mbps, so either way the memory will not be the limiting factor when transfering data from PC, and the transfer rate will be limited by the USB (or possibly by the PC itself). I cannot find which one of the specs is the Axim using, but it is one of the slow ones and I don't really have the time now to measure it, but internally, the fast processor can take advantage of the parallel access to the memory, that is whay I believe the backup was fast (in the original post).
i meant the transfer speed from pc to CF using a card reader/writer. no axim involved.
using the axim as a proxy to the CF is painstakingly slow. thats why i bought a card reader.
I just transferred a movie file (1,042,044,930 Bytes) to and from the Transcend 8GB 266X CompactFlash, from PC with Athlon 64 3200+ (2.21 GHz) CPU, 1GB RAM, using SATA-1 drive. It took it 275 secs to write and 250 secs to read that file. That would mean 3.8 MB/s and 4.17 MB/s write and read the SD with that PC. The card reader is a no brand thing I found somewhere, unpackaged, multi-card reader. I hope that is what you were asking. At the moment I am guessing that the PC is the key speed limitter, not the USB, which spec limits at about 50MB/s.
yes that is hat I wanted to know.
but i'm actually surprised by the speeds you are getting.
I have a standard sandisk 1GB card. (40x I think). not ultra I, or II, III, or even IV (266x) and the speeds i'm getting with an unbranded multi-card writer is an average of 1.9 megabytes per second. in other words a 100mb album (mp3 files) takes about 60 seconds to transfer.
based on this I would have thought that a 266x card would transfer at about 10/11 megabytes per second.
yes that is hat I wanted to know.
but i'm actually surprised by the speeds you are getting.
I have a standard sandisk 1GB card. (40x I think). not ultra I, or II, III, or even IV (266x) and the speeds i'm getting with an unbranded multi-card writer is an average of 1.9 megabytes per second. in other words a 100mb album (mp3 files) takes about 60 seconds to transfer.
based on this I would have thought that a 266x card would transfer at about 10/11 megabytes per second.
That assumption would be true if the transfer times depended strictly on the memory speed, but please realize that there is still control software, formating the data for the transfer and then unravelling it back out both for the disks as well as for the USB (packetizing, CRC's, controls, parity information and such), which is sometimes done by the H/W and sometimes by the S/W drivers, OS, etc). The multiplier has to do with CPU/Bus speeds, so these will be differrent in different PCs and finally the control chip inside the reader. By that I mean that the final transfer speed will only partially depend on the speed of the memory, just as speed of your PC would not quadruple if you use four times faster DRAM. The speed of the CF will be mostly realized when used by the Axim itself, but even then it will not quadruple. That is why there is endless running of benchmarks, actual S/W etc. when comparing any PC H/W. Sometimes faster H/W brings no improvement at all, because the actual H/W speed is negligible, depending of how much it is being accessed.
In previous post I was pleased because the backup speeds were fairly nice, and these were 250% better than the 150x Transcendent SD card. That is because the bus speeds and widths as well as the H/W drivers are different. By your assumptions the improvement should have been much less even in this much more equitable environment. The PC complicates the situation much more, specially comparing different PCs.
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