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Performance of 1GB DDR333 memory

Posted on 2005-03-14
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hi all,

i am going to buy 2 sticks of 1GB memory for my new laptop. i have tested 2 kinds of 1GB memory on the laptop and found that the benchmark results are only a half of that of the previously built-in samsung memory. the detailed information is as follows:

Benchmark software: PC Wizard 2005 version 1.643
OS: Windows XP

Memory Global Benchmark of Samsung 256 MB:
Bandwidth 1 KB                            8054.08 MB/s
Bandwidth 2 KB                            8259.86 MB/s
Bandwidth 4 KB                            8242.86 MB/s
Bandwidth 8 KB                            8138.29 MB/s
...
Bandwidth 1 MB                           4569.80 MB/s
Bandwidth 2 MB                           4377.88 MB/s
Bandwidth 4 MB                           1757.96 MB/s
Bandwidth 8 MB                           1728.31 MB/s
...
Bandwidth 128 MB                        1714.50 MB/s
Latency                                         149.09 ns (164 cycles)

Memory Global Benchmark of  PNY 1GB:
Bandwidth 1 KB                            5274.30 MB/s
Bandwidth 2 KB                            5345.30 MB/s
Bandwidth 4 KB                            5449.25 MB/s
Bandwidth 8 KB                            5270.50 MB/s
...
Bandwidth 8 MB                           1116.19 MB/s
Bandwidth 16 MB                         1100.52 MB/s
Bandwidth 32 MB                         1106.89 MB/s
Bandwidth 64 MB                         1113.48 MB/s
...
Bandwidth 1024 MB                      1107.05 MB/s
Latency                                         231.77 ns (165 cycles)

Memory Global Benchmark of  VDATA 1GB:
Bandwidth 1 KB                            4450.31 MB/s
Bandwidth 2 KB                            4548.63 MB/s
Bandwidth 4 KB                            4586.30 MB/s
Bandwidth 8 KB                            4431.75 MB/s
...
Bandwidth 8 MB                             943.34 MB/s
Bandwidth 16 MB                           939.87 MB/s
Bandwidth 32 MB                           933.75 MB/s
Bandwidth 64 MB                           940.48 MB/s
...
Bandwidth 1024 MB                       940.76 MB/s
Latency                                        274.99 ns (165 cycles)

it seems the results show: Samsung is much better than PNY, PNY is better than VDATA, right?

why 1GB memory has so lower performance than 256 MB one? or, the 2 kinds of 1GB memory are garbage? which type of 1GB DDR333 notebook memory do you prefer?

any comments are welcome!

regards,
bbao
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Question by:bbao
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25 Comments
 
LVL 15

Expert Comment

by:davidis99
ID: 13535302
You should check the samsung memory to find out whether it's CL3, CL2.5, or CL2, then check the other brands to find out if they're the same CL rating.   The CL rating indicates the memory latency, with a lower number indicating lower latency and therefore faster response.  See

http://www.pcworld.com/howto/article/0,aid,113460,00.asp

for a more detailed explanation.  If the Samsung RAM is CL2 and the others are a higher latency, that would explain the dramaitcally lower performance.
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LVL 15

Expert Comment

by:davidis99
ID: 13535343
Implied in my response, though I should have said it, is that whatever RAM you purchase should be for the CL rating specified for your laptop for optimal performance - RAM with a higher latency will either perform not as well, or in some systems not work at all.
0
 
LVL 37

Author Comment

by:bbao
ID: 13535506
thanks for your quick response. umm.. how can i check the CL rating? the machine is a laptop, i have checked its BIOS settings, there is no such a detailed and advanced setting for memory chip... :(
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LVL 37

Author Comment

by:bbao
ID: 13535533
did you notice the Latency data in the question? is it the latency number you were referring?
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Expert Comment

by:davidis99
ID: 13535716
You'll want to check the manual for your laptop, or the manufacturer website, for your laptop's technical specifications.  The latency numbers you provided do give me some idea about which items are running at which latency (your Samsung memory is probably CL2, while the PNY and VDATA are close enough that they could both be CL3, or possibly one is CL2.5 and other CL3.)
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LVL 37

Author Comment

by:bbao
ID: 13535841
just ran CPU-Z v1.26 and obtained the followings:

Module Size: 1024 MB
Max Bandwidth: PC2700 (166 MHz)
Manufacturer: 0000000000000000 ----> looks bad? :((

SPD Timing Table:
         Frequency   133 MHz   166 MHz
    CAS# Latency      2.0          2.5  ----> the current CL rating is 2.5?
   RAS# to CAS#       3             3
RAS# Precharge        3             3
              TRas#        6             7

the 2 kind of 1GB memory module are not good enough?

thanks in advance,
bbao
0
 
LVL 15

Expert Comment

by:davidis99
ID: 13537235
What's the model number of your laptop, and what are the model numbers of the memory modules you purchased?
0
 
LVL 37

Author Comment

by:bbao
ID: 13537276
my laptop is Acer TravelMate C112TCI (tablet PC), the 1GB memory module under test is VDATA 1GB.
0
 
LVL 15

Assisted Solution

by:davidis99
davidis99 earned 600 total points
ID: 13540979
Checking Acer's website for the system specs and checking one of the better US memory websites (crucial.com) for RAM for your system, I found that your system does NOT need PC2700 RAM, it needs PC2100 RAM - the Acer.co.uk page for the Travelmate lists the following specification:

http://www.acer.co.uk/acereuro/page9.do?dau34.oid=2956&UserCtxParam=0&GroupCtxParam=0&dctx1=17&ctx1=UK&crc=1239666479

"System Memory      Standard DDR-266 RAM, upgradeable to max. 2048MB* on dual soDIMM sockets (*depending on availability of 1024MB modules) 512 KB Flash BIOS; shadow RAM support"
 
And nowhere on the website or in the user manual does it give any detailed information about the type of RAM you need for this notebook.  Fortunately, crucial.com is one of the larger memory vendors in the world, and with their relationships with manufacturers, can often provide better info. about the type of RAM needed for a system than the manufacturer.  

According to crucial's website,

http://www.crucial.com/store/listparts.asp?Mfr%2BProductline=Acer%2BTravelMate&mfr=Acer&cat=RAM&model=TravelMate+C110+Series&submit=Go

you need PC2100 (DDR-266) RAM running at CL-2.5 speed.  It appears that the faster (DDR-333) RAM was not designed to work properly in this laptop, or the laptop simply can't accept RAM other than what it's designed to use, and that is very likely the cause of the problem you're experiencing with trying to use RAM that this Acer can't use.
0
 
LVL 37

Author Comment

by:bbao
ID: 13541867
thanks for your informative reply. does it mean that, using PC2700 modules (DDR333) on a PC2100 system may produce even lower performance than PC2100 modules (DDR266)? i have checked my CL ratings, it seems the system works at CL2 with the Samsung chips, at CL2.5 with the 1GB modules, though the 1GB ones are at 166 MHz. that's what dont understand. :(

AFAIK, DDR333 should be compatible with DDR266,  or in other words, a 333 module can be used on a design-for-266 system, althought it might just act as 266 chips. am i right?

regards,
bbao
0
 
LVL 37

Author Comment

by:bbao
ID: 13541975
moreover, my tablet is C112, which supports up to 2GB memory. at the moment, i am just writting this comment on the tablet with 2GB memory on board. the crucial's website says C110 series support only 1GB, i am afraid it is wrong, at least for its latest models:

"System Information for the Acer TravelMate C110 Series:
    * System Type: Laptop/Notebook
    * Maximum memory: 1024MB
    * Standard memory: 128, 256, or 512MB removable
    * Slots/banks: 2 (2 banks of 1)"
0
 
LVL 15

Expert Comment

by:davidis99
ID: 13551863
kep in mind the acer website said

2048MB* on dual soDIMM sockets (*depending on availability of 1024MB modules)

and Crucial is only selling what actually is being manufactured now, whereas Acer is saying the higher capacity modules will work ONCE they're available.
0
 
LVL 37

Author Comment

by:bbao
ID: 13551887
i see davidis99. thanks. could you please explain more about what i asked at {#13541867}? regards,
0
 
LVL 37

Author Comment

by:bbao
ID: 13551903
btw, i have raised the points to 1000... :) waiting for the great answer... hehe.
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LVL 23

Accepted Solution

by:
sciwriter earned 800 total points
ID: 13552268
BBao -- you are missing the crucial points of RAM and losing the focus of what you need to look for.  Let me educate you, and  please don't take it lightly, as I have told many others this, and they seem unable to grasp the bottom-line reality of the situation.

Memory facts you quoted are irrelevant to how RAm synchronizes with a system bus.  It is ALL about timing -- if the RAM is dissynchronized to the bus, it will go out of sync, causing most memory problems.

The ram must be faster than or equal to the system bus, so it is always ready for the bus's data.  For almost ALL hi-performance MBs, you must have ram that is CAS LATENCY 2.5 ns or better -- any slower, and it is not ready for the system bus.  If you get CL 3.0, you are bound to have RAM too slow for the system.  Get CL 2.0 and it wil always be ready for the PCI bus and MB Bus BW to get data in sync from it.

So, bottom line, nothing slower than CL 2.5 for most hi-perf. MBs - some need CL 2.0.  Only the slow dogs work with CL 3.0 RAM.

That is the bottom line facts.  Nothing you quoted above is relevant.  Sorry, but those are the facts, RAM is all in the refresh speed, nothing else.
0
 
LVL 17

Assisted Solution

by:davebytes
davebytes earned 600 total points
ID: 13552853
Note that the SPD timing table is not how it IS running right now, but rather how the chipset manufacturer DESIGNED the chip to run.  So the 133Mhz/166Mhz table you listed is how the manufacturer SPECS those ram chips to run at those FSB speeds.  I think the table you pasted above indicates that if you crank up the FSB speed for those chips, they are expected to be run at a higher CAS latency -- you turn up the bus speed, but the memory has to be capped.  The 'Max Bandwidth' number is the RATING of the chip (that is, it is likely PC2700 ram...), not the speed it is BEING run at currently...

Your system runs at whatever speed it is set at -- if the bios offers no controls, and the above-mentioned docs are correct, you are probably running at 133Mhz FSB (DDR266/PC2100... fun all the damn numbers!!!).  Any memory you get will actually be run at that Mhz speed, regardless of its rated speed.  While you can generally run higher-speed-rated ram at a lower speed, there is no guarantee of how well it will function, nor that it will function 'better' than proper-speed-rated ram.

I would mostly agree with sciwriter, in that CAS latency -- and the other sub-ratings -- are critical factors in the overall performance of the system.  Though these days there are so many variables that impact overall system performance, including the memory controller on the motherboard.

-d
0
 
LVL 37

Author Comment

by:bbao
ID: 13552899
sciwriter, thanks for your informative educating. :)

so the key should be CL rating, lower is better, for speed matching between system bus and RAM. then, based on a matched system bus and RAM, the next thing should be considered as well is bandwidth, higher is better, related to the benchmark i mentioned in the question. am i right?

umm... some other things are also confusing me, too:

Module Size: 1024 MB
Max Bandwidth: PC2700 (166 MHz)
Manufacturer: 0000000000000000 ----> the 1GB modules dont have the manufacturer ID and serial numnbers, while the samsung ones have both of them. is it important?

SPD Timing Table:
         Frequency   133 MHz   166 MHz
    CAS# Latency      2.0          2.5  ----> why higher frequency means higher latency?
   RAS# to CAS#       3             3   ----\
RAS# Precharge        3             3   ----> how to determine the right ratings for my laptop and RAM?
              TRas#        6             7   ----/  could some one kindly give me some URLs for easy understanding?

regards,
bbao
0
 
LVL 37

Author Comment

by:bbao
ID: 13552962
davebytes, thanks for your comment, i just saw your message after posted my last comment.

> if the bios offers no controls, and the above-mentioned docs are correct,
> you are probably running at 133Mhz FSB (DDR266/PC2100... fun all the damn numbers!!!).

the BIOS of this ACER tablet PC does not have advanced settings for speed timing. :(
the source of the table above is not from the laptop document, it is from CPU-Z program.

according to the specification of the tablet PC, it needs Dual 200-pin soDIMM sockets supporting PC2700 DDR memory running at 333 MHz.

as for FSB, it should be 400 MHz, chipset INTEL 855GME.

any further comments on what kind of memory i should choose?

regards,
bbao
0
 
LVL 7

Expert Comment

by:crazijoe
ID: 13554824
I would probably buy whatever Crucial recommends.
0
 
LVL 17

Expert Comment

by:davebytes
ID: 13558606
You have some really confusing info there.  If your memory is running at a different speed than your FSB, you are never going to hit absolute optimal performance for your CPU, so I truly just wouldn't worry about it too much.  That's like running DDR400 ram with a new celeron with 533 FSB -- it isn't killing performance, it just isn't the absolute best/highest you could have.  It's a frequent thing these days! ;)

If you believe the specification for the tablet, find PC2700/DDR333 SODimms with at least a CL2.5 rating.  You can probably do fine with 2.5, though if you can spend the extra money and get a CL2, it will buy you a little bit.  If you buy via one of the online vendors, they will usually tell you the complete ratings.  If you buy from someone like NewEgg, so long as it isn't 'value ram', they usually list the ratings (i.e., your above ram might be listed as "2.5-3-3-7" on NewEgg).

If the memory bus is really running at 400Mhz and the specs are wrong, you want PC3200 SODimms.  In theory, if you get high-quality DDR400 SODimms, you should be able to run them at 333 with 'no penalty'.  But I'd trust whatever Acer specifies, OR whatever you can get a few INDEPENDENT online memory wholesalers to agree upon (a number of them are the same database, some are even the same store, so make sure it is completely different companies).

And just to reiterate, you have to be doing some SERIOUS heavy memory application use for the difference between ratings to truly make an impact -- i.e., actively running database queries on the tablet or something...  The percentage impact in real world time (seconds) the things we're discussing here will make is minimal.  The folks who really need low-latency, speed-matched ram are either hardcore gamers (need every % fps they can get), or server situations (constant over-memory allocation and use).  Well, and other heavyweight applications like workstation-level apps (photoshop, 3D modeling/rendering, etc.).

-d
0
 
LVL 2

Expert Comment

by:DRZCM
ID: 13559685
I wouldn't worry too much.  The difference in benchmarks will not be enough to offset the benefit you will get from having more memory.  You will see a big boost to your overall performance.  Also, the larger the modules the slower the performance of the chip itself (all things being equal).  There is simply more area to address and access.

Dr. Z
0
 
LVL 37

Author Comment

by:bbao
ID: 13583212
i appreciate all the experts who contribute their valuable comments above.

currently, the installed memroy modules are 2*1GB PHY Bravo DDR333 (i am sorry that Crucial's memory modules are not available here). here is more detailed information i learned from the utilities and official document:

* CPU-Z v1.26 - Dec 2004 *

CPU/Processor
- Name: Intel Pentium M 733
- Code Name: Dothan, Brand ID: 22
- Specification: Intel Pentium M processor 1.10 GHz
- Instructions: MMX, SSE, SSE2

CPU/Clocks
- Core Speed: 600.0 MHz
- Multiplier: x 6.0
- FSB: 100.0 MHz
- Bus Speed: 400.0 MHz

CPU/Cache
- L1 Data: 32 KB
- L2 Code: 32 KB
- Level 2: 2048 KB

Memory/General
- Type: DDR-SDRAM
- Size: 2048 MB

Memory/Timings
- Frequency: 166.7 MHz
- FSB:DRAM: 3:5
- CAS# Latency:            2.5 clocks
- RAS# to CAS# Delay:    3 clocks
- RAS# Precharg:            3 clocks
- Cycle Time (Tras):        7 clocks

SPD
- Module Size: 1024 MB
- Max Bandwidth: PC2700 (166 MHz)
- Manufacturer: 0000000000000000
- Correction: None
- Registered: No
- Buffered: No

* PC Wizard 2004 v1.632 *

Benchmark/Memory Global Benchmark/Information
- Processor: Intel Pentium M
- Freqency: 600.02 MHz
- L1 Cache: 64 KB
- L2 Cache: 2048 KB
- Total Memory: 2040 MB
- Front Side Bus Speed: 100 MHz
- Bus Speed: 400 MHz (QDR)

* TravelMate C110 Specifications *
http://aac.acer.com/app/akc/internet/rwpgslib.nsf/graphic+files/DatasheetTMC110/$FILE/Datasheet_TMC110.pdf

"Platform/Intel Centrino mobile technologies
- Processor: Ultra Low Voltage Intel Pentium M processor at 900 MHz and higher; 1 MB L2
- Chipset: Intel 855GM chipset with 400 MHz FSB
- Wireless solution: Integrated Intel PRO/Wireless 2100 or 2100A5 network connection"

it seems that ACER officialy states above that its FSB is 400 MHz, that is why i mentioned "as for FSB, it should be 400 MHz, chipset INTEL 855GME" in my last comment. it might be NOT correct i think now.

BTW, another weird thing is that the PC Wizard 2004 reports different benchmark result each time i run it, of course with the same PNY modules installed and no additional applications loaded, e.g. Bandwidth 1KB @ 4000+MB/s, 6000+MB/s or even 8000+MB/s. i am really stuck here. :((

Regards,
bbao
0
 
LVL 37

Author Comment

by:bbao
ID: 13583234
BTW, i am really very sorry for that it seems i can NOT offer the 1000 points (this question and the link question) for awarding the experts here because i have been told, by a CS admin, that this "is a violation of the rule" which even does not allow graciously passing points between questions, it should be allowed before 2004 as i remember.

although i am expecting to award more points to you guys, as what i promised above, but now it seems that i have to say more THANKS to you instead of offering the points. i am SORRY, and THANK YOU GUYS VERY MUCH!

sincerely,
bbao
0
 
LVL 37

Author Comment

by:bbao
ID: 13583251
0
 
LVL 37

Author Comment

by:bbao
ID: 13778588
the points were split. the points should be doubled but only THANKS could be doubled here. hehe. :)
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