Transcend JM366D643A-50

Transcend will be best known to some of our readers as a manufacturer of flash memory. While flash memory is an important product line for Transcend, they also manufacture storage products and system memory. You will not find Transcend for sale at a huge number of US websites, but Transcend also sells directly to end-users at their website. Transcend has US sites in both Spanish and English, as well as several European language sites, and Taiwan, Japan and China websites.

The 1 Gigabyte of DDR400 arrived as two separate 512MB DIMMs. Transcend packaging is very similar to that used by Kingston for their value products.

There are no heatspreaders on the Transcend CAS 2.5 DIMMs. The memory chips are labeled JetRAM, which is a name used by Transcend for their memory chips. A quick check found 1GB of Transcend CAS 2.5 selling for around $100, which is a lower price than what we normally see for a CAS 2.5 memory.


Transcend rates JM366D643A-50 at DDR400 CAS 2.5 and we found the "auto" or SPD timings to be 2.5-3-3-8.

 Transcend JM366D643A-50 (DDR400) Memory Specifications
Number of DIMMs & Banks 2 DS
Total Memory
512 MB
Rated Timings 2.5-3-3
SPD (Auto) Timings 2.5-3-3-8
Rated Voltage 2.6V

Transcend shows both DDR400 CAS 2.5 and DDR400 CAS 3 in their product list, so it is clear that the DIMM products from Transcend are aimed at the Value end of the memory market.

Test Results

Transcend JM366D643A-50 - 2 x 512Mb Double-Bank
CPU Ratio at 2.4GHz Memory
Memory Timings
& Voltage
Sandra UNBuffered Sandra Standard
Super PI 2M places
(time in sec)
Wolfenstein - Radar - Enemy Territory fps
12x200 400 DDR 2.5-3-3-6
2.6V 1T
532.0 INT 2420
FLT 2593
INT 6050
FLT 6036
82 111.9
11x218 436 DDR 3-3-3-6
2.8V 1T
529.2 INT 2593
FLT 2735
INT 6393
FLT 6309
82 111.7
Highest CPU/Mem Performance 3-3-3-7
2.8V 1T
575.5 INT 2668
FLT 2835
INT 6650
FLT 5516
75 122.5
To be considered stable for test purposes, Quake3 benchmark, UT2003 Demo, Super PI, Aquamark 3, and Comanche 4 had to complete without incident. Any of these, and in particular Super PI, will crash a less-than stable memory configuration.

Transcend is another memory that costs just $100 for a Gigabyte and yet manages to nearly reach DDR450 in overclocking. The cost and performance are very similar to the Kingston CAS 3 rated Value RAM except that Transcend rates its Value RAM at CAS 2.5. While the rated timings differ, both Kingston and Transcend both are stable at CAS 2.5 at DDR400. The Transcend RAM is an excellent value and provides the overclocking capabilities to reach a 12% CPU overclock at 1:1 memory ratio.

We have looked at Aida 32 results in the past, and found them to be very useful in examining read/write performance and memory latency. Aida 32 is now available as Everest Home Edition, a free download from

Transcend JM366D643A-50 (DDR400) 2x512Mb Double-Bank
Everest 1.51
CPU Ratio at 2.4GHz Memory Speed Memory Timings
& Voltage
Everest READ
Everest WRITE
Everest Latency
12x200 400 DDR 2.5-3-3-6
2.6V 1T
5801 1861 47.7
11x218 436 DDR 3-3-3-6
2.8V 1T
6028 1906 48.8
Highest CPU/Mem Performance
446 DDR
2.8V 1T
6306 1989 47.9

It is easy to see in the Everest results that dropping CAS just from 2.5 to 3 in moving from DDR400 to DDR436 offsets virtually all of the performance improvements that you get from higher memory speed. The $100 Transcend reaches on to DDR446 to give you most of the headroom that you need for air-cooled 1:1 overclocking at stock multipliers.

OCZ PC3200 Gold: "Value BH5" Performance Comparisons


View All Comments

  • LoneWolf15 - Wednesday, April 13, 2005 - link

    Thanks for a good article. I usually post response for constructive criticism, but I ought to balance that out more. The Value VX OCZ RAM was particularly interesting and worth knowing about. Reply
  • Wesley Fink - Wednesday, April 13, 2005 - link

    #79 - I double-checked the part number on the OCZ "Value BH5" and corrected the Part Number on page 2. Thanks for pointing this out. Reply
  • ericeames - Wednesday, April 13, 2005 - link

    I belive that the idea of this roundup was good but it has some flaws:

    I dont think that getting memories directly from the manufacturer is a good idea. I know that this is how it "works" it makes the result less credible!

    The overclocking possibilities is not THAT important altough it should not be neglected.

    Compairing them with better brands was a good idea, it makes the results relative.


  • srstudios - Wednesday, April 13, 2005 - link

    Wesley, it seems that the part number is incorrect for the BH-5 OCZ shown on page two.

    ELDCGE-K for BH-5 2-2-2

    Nice article though, thanks for all the great work!
  • srstudios - Wednesday, April 13, 2005 - link

  • xsilver - Tuesday, April 12, 2005 - link

    another thing I have to clear up..... I don't mind extreme voltages used on a "performance" review but this was supposed to be a "VALUE" roundup.... so in this situation extreme voltages may not be warranted

  • xsilver - Tuesday, April 12, 2005 - link

    #62 wesley... you continiued analogy is flawed....
    the thing you forget to mention is that the ferrari only smokes the chevy IF and ONLY IF the racing alcohol is used (3.4v) and the racing alchohol is only available to people who buy say brand X tyres (dfi board).... so in essence you cannot separate the dfi board and the vx + bh5 ram.... they must be used together.....
    I stand by my statement that this "review" smells a bit like an advertisment for dfi and ocz

    I thought it was generally accepted that you can now get the same performance with 1:1 overclocking on loose cas3 timings as a lower mhz with tighter cas 2 timings.... so the need to push the ram to the highest mhz is unnessessary to get the best performance
  • JustAnAverageGuy - Tuesday, April 12, 2005 - link

    Poor Wesley.

    The crowds can never be pleased.
  • AtaStrumf - Tuesday, April 12, 2005 - link

    ChineseDemocracyGNR's post reminded me of one more thing that is sooooo... wrong with this article. 240MHz is nowhere near enough for 1:1 OC-ing of A64s, because unlike you, we don't have 2,4 GHz (4000+, 939, 12x multiplier) chips which cost a fortune, but rather 1,8/2,0 GHz (3000+/3200+, 939, 9x/10x multiplier) chips which cost much less. So if you do the math that is 2160/2400 MHz, which is not exacly the limit, at least not anymore, now that the 90 nm Venice chips are just around the corner. Reply
  • AtaStrumf - Tuesday, April 12, 2005 - link

    I noticed that typo too Olaf van der Spek, but more importantly this very same Transcend RAM gave me quite a bit of trouble and I would not recommend it to anyone with an A64. I was getting strange errors on my ABIT KV8 K8T800Pro, A64 3200+ S754, 2x512 transend RAM combo, like consistent NERO Identity check failures after a DVD burn. Really annoying!!! There were other stuff too, but the point is after I switched to TwinMOS Twister 3700, PQI OEM 3200, Geil Value 3200, Crucial Ballistix 3200 CL2 (best RAM I tested so far), Corsair XMS 3700 (crap RAM BTW), APACER 4000 (TCCD chips; on A64 won't run with any other stick, eg. 1x512 Ballistix + 1x512 APACER, system only sees 512MB of APACER RAM; checked with many different memories) or any other memory for that matter, everything worked just fine, so there is something really strange wrong with Transcend RAM so I strongly recommend that all A64 users avoid it like a plague.

    I agree that the only good choice in this roundup was a OCZ VX Value. You shouldn't let manufacturers pick the RAM you test. Ask us what we want to see tested, we'll have plenty of ideas. The ones I'd like to see are Corsair Value (which I know is crap, I just want you to show in Anand's recent blog entry AT's much advertised backbone and prove to Corsair that you will not take their BS excuse and will still test their RAM, even if they don't want you to, because we, the readers, come first), then GEIL Value 3200 isn't all that bad, then TwinMOS Speed Premium, PQI 3200 OEM, Geil pc4000 Ultra Platinum isn't that expensive either.

    And please stop at 2,9V, because that is as high as most are willing to go, and don't test more that CAS 2.5 and 1T.

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