help me upgrade my RAM

[rajivpa]

Hi

I recently bought Thinkpad T43 - 2668-6GU, well love that machine, learning to live with fan noise though.

Originally my system had 512 RAM, now I need to run IDEs and other application on this notebook, thought if I could upgrade the RAM to 1 GB performance would be optimum.

Please suggest how should I go about this upgrade, like where to find what kind of RAM i need, where to order etc.

Would greatly appreciate any help

Thanks

Rajiv

[rosemarycane]

Here is my two cents:

option 1: you could purchase the ram directly from the Lenovo website. Realize that you will be paying a premium for "their" ram.

option 2: check out newegg. I have actually been thinking about upgrading my ram as well. They offer notebook memory from crucial, mushkin, corsair and others. Their prices tend to be much better than other venders.

Hope this helps.

[rosemarycane]

Sorry, forgot to mention that I also have a t43 model 2668. You would need a 200 pin sodimm 4200 ddr2. You can get another stick of 512 from lenovo to enable dual channel, or purchase a one gig stick from newegg.

hope this helps

[kam_]

I went crucial direct. Its got a lifetime waranty anyway so why pay IBM a pemium for the same type of ram. 2x1GB here

[rajivpa]

And is there any changes required to BIOS etc or it detects the new RAM automatically ?

[DIGITALgimpus]

I second Crucial (I really like them). If you buy OEM Crucial through someone like Newegg, it's even cheaper than direct (though read the find print, crucial.com has some guarantees).

[bill bolton]

And is there any changes required to BIOS etc or it detects the new RAM automatically ?

It will detect it automagically, you don't need to do anything other than plug the RAM card into the socket.

Cheers,

Bill

[davidspalding]

Sorry, forgot to mention that I also have a t43 model 2668. You would need a 200 pin sodimm 4200 ddr2. You can get another stick of 512 from lenovo to enable dual channel, or purchase a one gig stick from newegg.

hope this helps

I think I read here that this "dual channel" is a myth. Do you have any docs which corroborate this? What's required - equal amounts, or "some special" RAM?

(I also got a 1 gb stick from NewEgg.com, works fine.)

[brentpresley]

Sorry, forgot to mention that I also have a t43 model 2668. You would need a 200 pin sodimm 4200 ddr2. You can get another stick of 512 from lenovo to enable dual channel, or purchase a one gig stick from newegg.

hope this helps

I think I read here that this "dual channel" is a myth. Do you have any docs which corroborate this? What's required - equal amounts, or "some special" RAM?

(I also got a 1 gb stick from NewEgg.com, works fine.)

Could someone with a T43 please run some tests so we can prove/refute the dual channel argument for the Sonoma chipset?

Memory benchmarks (Sandra, memtest86+, etc) running 1 x 1GB and 2 x 512MB would be great.

[DIGITALgimpus]

I've got a 1GB, and a 512MB card in, and according to most software, it's running in dual channel mode.

[brentpresley]

I've got a 1GB, and a 512MB card in, and according to most software, it's running in dual channel mode.

That doesn't make sense. In all dual channel desktops, they memory has the paired size-wize.

What is "most software"?

[davidspalding]

I'm reading more, but this stood out:

DDR2 Memory In Dual-channel Mode Does (hardly) Anything In Practice.

This is only one reviewer's findings, so take with grain (or lost shaker) of salt. Frankly, the other discussions of "dual channel" versus "single-channel" memory are confusing. I can't find reference in my system specs, or in the Kingston memory that I ordered from NewEgg.com, to "dual channel" memory.

[edit] Here's another interesting page about this. Seems to indicate they used two identical-sized modules, but the article specifically mentions the benefit "When a pair of modules are used, the DDR2 data path effectively increases from 64-bits to 128-bits."

http://laptoplogic.com/resources/detail ... =20&page=3

[kam_]

Well the principle is quite simple. You have one channel to each memory bank.

With single channel if you want to store something to ram, you store it in bank 1, or bank 2. So lets take an example. Store two 32 bit numbers.

You put then in memory location location 0x00000000 and 0x00000001 of bank 1.

When the CPU needs to read both bytes back you send a request for byte 0x00000000. Once the data is returned, you send a request for byte 0x00000001.
The total time to retreive 2 bytes is 2 memory read cycles.

With dual channel, you put the first number in location 0x00000000 of bank 1, and the second number in location 0x00000000 of bank 2. When the CPU requests both byte back, it sends a request for byte 0x00000000 in bank 1, and the same in bank 2. The memory reads happen in paralel down because they are sent down independant memory channels.

The bandwidth is efectively doubles from 32bit to 64bit i.e. you can retreive 64 bits at a time with dual channel, rather than 32 bits with single channel.

Even with 1024mb and 512mb, you could in theory run half the memory in dual channel, and the remaining 512mb of the first DIM would run in single channel.
BUT thats not a configurable option, and isn't suported. It would just add more latency in memory mangament, and outweight any advantage you got with the dual channel configuration.

This is why they say that having 2 identical DIMs enables dual channel. The speed of the DIM's also matters. Because if one reply comes back before the other the CPU has to deal with this. In theory its still faster than single channel, but 2 identical memory DIMs with identical speed are the best option.

In practice it makes such a small fraction of a difference UNLESS you are doing large block reads. Large block writes have an even more significant difference because memory writes take longer than reads (because of a commit time). This is exactly why shared memory graphics card should show better benchmarks with dual channel, but other configurations probably won't.

EDIT:

I just saw that last article.. it explains quite well that although you have seperate channels, there are still bottlenecks because all resource mesages still go down a single FSB. The theory is that the memory read, and memory write are the slowest parts of the process. The sending of the actual data down the bus can be buffered, and even if send serially, as long as the actual memory read/write happens in parallel you see a huge speed difference. In reality memory read/write is quite well buffered too, so you'll only see that big difference in large block reads/writes where that buffer overflows and you are forced to wait for pending operations to finish.

[DIGITALgimpus]

I'm reading more, but this stood out:

DDR2 Memory In Dual-channel Mode Does (hardly) Anything In Practice.

Dual Channel only helps if you do work with massive i/o with the system memory... the vast majority of people don't (even most gaming doesn't qualify).

It's 90% hype, but for people who need it, it does provide an advantage. Though don't think it doubles your performance... not even close. There are too many other bottlenecks in a system.

[kam_]

exactly.... the huge cache's now mean that even large block read/writes get buffered for you. Only buffer overflows - VERY large block read/writes which overflow those buffer will show speed increases.

[davidspalding]

Thanks, kam_, that makes it a lot clearer. So IOW, the system recognizes that both DIMMs are same-sized, and dual-channel mode goes "ON." So long as they're the same speed (e.g. 533 Mhz).

Sounds like ordering another 1 GB stick to replace my IBM 512 MB stick would do nothing more than ... give me 512 MB more ram.

Though ... I use Photoshop and Premiere Elements ... perhaps I WOULD see a little teeny performance boost in filters and stuff on images > 2 MB in size (i.e. Camera Raw images). Dunno. I'm about to order a hard drive anyway, anyone think a 512 MB PC2-4200 stick would sell quick here in the Sell forum?

BTW, I'm still interested in what programs would report/confirm that memory is in single-channel or double-channel mode.

[kam_]

Personally i think there are a very few specific types of programs that will show you big differences in speed. For most things, probably including photoshop with large images you're much better off investing in a faster hard drive (highest spindle speed you can afford and the biggest cache).

[bill bolton]

For most things, probably including photoshop with large images you're much better off investing in a faster hard drive (highest spindle speed you can afford and the biggest cache).

"For most things", more memory beats higher spindle speed hands down in terms of overall system performamce. While higher spindle speeds feel somewhat "snappier" when handling files, the name of the game in overall performance of most applications is not going to disk unless you have to.

Cheers,

Bill

[gunston]

"When a pair of modules are used, the DDR2 data path effectively increases from 64-bits to 128-bits. This doubles the theoretical memory bandwidth from 4.2 GBytes/sec to 8.6 GBytes/sec"

This means that pair of memory module are the similar brand?

[DIGITALgimpus]

"For most things", more memory beats higher spindle speed hands down in terms of overall system performamce. While higher spindle speeds feel somewhat "snappier" when handling files, the name of the game in overall performance of most applications is not going to disk unless you have to.

Cheers,

Bill

Very true, though only if you suffer from disk latency.

Most PC's suffer due to disk bandwidth (not the same as latency). That's fixed by upgrading to SATA (not much benefit IMHO), SCSI (a bit faster), or a RAID configuration (very good, but extremely costly). Is it worth the cost for these fixes? In 98% of the cases, no.

People have this idea of just "throw hardware at it" to fix a problem... just don't do that.

Find your bottleneck, and fix THAT. That's the best way to improve performance.

It's partially the system you run, but mostly how you use the system. I'm a student/developer... lots of disk i/o, but even more apps running (just my style of working). So I upgraded RAM to 1.5GB, and kept the 5400RPM drive (though it's now 100GB) for battery life reasons.

Throwing money at a problem doesn't fix it. It's finding the source of the problem. To many times it seems people forget that.

[kam_]

For most things, probably including photoshop with large images you're much better off investing in a faster hard drive (highest spindle speed you can afford and the biggest cache).

"For most things", more memory beats higher spindle speed hands down in terms of overall system performamce. While higher spindle speeds feel somewhat "snappier" when handling files, the name of the game in overall performance of most applications is not going to disk unless you have to.

Cheers,

Bill

ERM... i'm talking about the difference between single channel at 2GB and dual channel at 2GB. I'm not at all saying that a faster hard drive is better than more memory in most cases. However it IS if your data will always go to disk, and is much bigger than any physical ram you could buy. But that wasn't the point anyway, it was about dual channel.

Rather than invest in changing your DIMMs around to get dual channel the money is better spent on a better hard drive. Like i said, dual channel only offers a big speed advantage when you make block reads or writes which overflow the internal memory caches. In that case reads/writes are blocked until pending operations are complete.

If you had read earlier, you would have seen this was specifically related to large block writes where the data WILL go to disk (large images in photoshop), simply because the memory isn't going to be large enough. In ANY case faster spindle speed reduces seek times. In THIS particular case a very large disk cache is very beneficial because of the large block read/writes.

It was an answer to a very specific case!

Its pretty simple really..

In a dual channel configuration:

- Memory reads/writes in small chunks - no real speed improvement
- Memory reads/writes in large chunks, less than the memory cache - no real speed improvements
- Memory reads/writes in large chunks much LARGER than the memory cache but smaller or close to physical memory - big performance increase
- Memory reads/writes in large chunks LARGER than the memory cache, and much larger than the physical memory - no real performance increase. In THIS particular case the money is definately better spent on a faster hard drive with as big a cache as you can afford.

[bill bolton]

If you had read earlier, you would have seen this was specifically related to large block writes where the data WILL go to disk (large images in photoshop), simply because the memory isn't going to be large enough.

This is not a "most cases" scenario.

Cheers,

Bill

[kam_]

oh for god sake, that was with regards to dual channel vs single channel and a reply to the post preceding it where davidspalding wrote:

'Sounds like ordering another 1 GB stick to replace my IBM 512 MB stick would do nothing more than ... give me 512 MB more ram. '

He was refering to the extra 512mb only giving him memory benefit, and the dual channel not adding anything on top of that - my reply in that context:

'Personally i think there are a very few specific types of programs that will show you big differences in speed. For most things, probably including photoshop with large images you're much better off investing in a faster hard drive (highest spindle speed you can afford and the biggest cache).'

we were having a split discussion on dual channel vs single channel. I don't know how much clearer i can make it. I'll just shut up now.

[davidspalding]

For most things, probably including photoshop with large images you're much better off investing in a faster hard drive (highest spindle speed you can afford and the biggest cache).

Scratch disks and faster disks may help a little, but Photoshop gets much zippier with >= 1 GB RAM, particularly if you enable the "big blocks" option for memory use. You'll find this all over the Photoshop guru sites, three things help PHotoshop performance, "memory, memory and more memory."

This means that pair of memory module are the similar brand?

I surely hope not. As long as the memory is same spec (e.g. DDR2 PC2-4200 533 Mhz), they should work. Right, experts?

'Sounds like ordering another 1 GB stick to replace my IBM 512 MB stick would do nothing more than ... give me 512 MB more ram. ' ....

And I was mistaken. Because in the case of matching my memory DIMMs, enabling dual-channel mode, I could see performance increases of -- wow -- 10 or 15 seconds in Photoshop with images about the size of many raw camera files. Though scratch disk speeds help out, when Photoshop is running filters, and using RAM for processing, doubling the bandwidth (dual- versus single-channel) to the RAM probably makes a diff. As these reviewers clearly found:

To test Photoshop CS performance, we used the DriverHeaven Photoshop V2 benchmark script, which performs various operations on a huge 5610x3740 image.

... As you can see from the results, 1GB RAM rules. Despite the obvious landslide in favor of 1GB system RAM, dual channel or not, there is also a very tangible performance increase when going to dual channel with only 512MB RAM. Photoshoppers should shoot for 2x512MB or even 2x1GB memory configurations, as this is one area where Sonoma's dual channel capability really shines.

... Photoshop CS does show a measurable performance increase with dual channel 512MB, shaving 23.4 seconds off our total Photoshop processing time. However with most applications that will benefit from dual channel implementation, like Photoshop, more RAM usually brings more performance than dual channel. From this writer's standpoint, it is better to buy a 1x1GB stick of DDR2 RAM rather than 2x512MB DDR2.

No need to feel put upon, Kam_, no one's contesting your helpful information on the dual-channel spec. I'm just contesting what I presumed about adding another 512 MB to my system, and enabling dual-channel operation. Adding a faster hard drive isn't nearly as much help to Photoshop than adding RAM ... and in this case, as per your information, I will get a dual-boost from matching my 1 GB stick. If y'all like, I'll run my own tests as did these guys. It'll just take me a while to get to it, life's busy at teh moment.

[kam_]

I take your point about memory and everyone else's. More memory -> faster performance. But i'm talking specifically dual channel against single channel at the same physical memory size. I agree with all the speedups you claim or the site you said claims, as i said:

- Memory reads/writes in small chunks - no real speed improvement

- Memory reads/writes in large chunks, less than the memory cache - no real speed improvements

- Memory reads/writes in large chunks much LARGER than the memory cache but smaller or close to physical memory - big performance increase
^^^^ Thats brush manipulation right there.. perhaps i should have added 'free physical memory' not just physical memory per se.

- Memory reads/writes in large chunks LARGER than the memory cache, and much larger than the physical memory - no real performance increase. In THIS particular case the money is definately better spent on a faster hard drive with as big a cache as you can afford.

Block mode i imagine initiates a block write within the memory chip itself, which can be pipelined to speed things up.

About the memory being the same, it only needs to be the same speed and type. Every single module has slightly different speed characteristics, so no two modules will ever read at exactly the same time. Thats what the memory cache is for. The same type and speed on the label will enable dual channel, and in theory the closer the exact read/write speed of the modules the faster everything will run - in practice this last point makes no real world difference.