What's the deal with RAM running dual channel? 6

[blackranger]

I recently talked to a sales guy at ibuypower.com.(internet computer building company) I wanted to know why they don't offer any options in their custom built "gaming" laptops for more RAM than 2GB. There are a ton of other laptops out there that offer 3GB or even 4GB of RAM. He said that Vista 64 bit doesn't have any drivers out yet and that's why they don't use 4GB, and he said that when you run 3GB in dual channel you will be unstable and your pc will run slower than if you were just running 2GB RAM dual channel.
When I asked him why other people are doing it, he said that it is just advertising to draw people in and that they probably disable dual channel before they sell the computer to people.????

What am I missing about how dual channel works and if he has a point, why are big name manufacturers selling their high power laptops with 3GB or 3.5GB (that's 4GB in 32bit Vista minus the 512mb video card) like there's no problem? Alienware and Dell XPS have laptops with 3 and 3.5 RAM.

Any insight would be appreciated...

 

[paparazi]

With 32bit Vista he pretty much acurately describes the current situation.
I'm not so sure about the instability claim with 4gig but he certainly has a point with machines using 3gig and loosing out on dual channel.
Martin

On wings like angels whispers sweet
my heart it feels a broken beat
Touched soul and hurt lay wounded deep
Brown eyes are lost afar and sleep

 

[gobleza]

I don't see why running 3g would be unstable in dual,
If you use 2 * 1g ram chips and 2 * 512m, making sure that you place them in the corresponding slots. You will not loose out on the dual channel, provided that you ut the different ram sizes in corresponding slots. Just make sure that all the ram is of the same speed otherwise it runs at the lowest speed, from what I understand.

John

 

[paparazi]

gobleza
Hmmmmmmm never seen a laptop with four memory slots! which model is it you are talking about.
Martin

On wings like angels whispers sweet
my heart it feels a broken beat
Touched soul and hurt lay wounded deep
Brown eyes are lost afar and sleep

 

[tf1]

To install 4GB memory would require 2 x 2GB modules for a laptop (as they all have just 2 slots) and at the moment, 2GB modules are more than double the cost of 1GB modules (thought that will change one day). This is only a supply/demand thing: there just isn't a big demand for 2GB SODIMM modules at the moment.

If you stick in 3GB, you will have 1 x 2GB plus 1 x 1GB modules installed. The can only run in single channel mode as you need 2 identical modules to operate in dual channel mode.

In my experience, Vista 32-bit runs slower with 4GB memory installed and it cannot use much more than 3 GB anyway. Far better to install the 2 x 1GB and get a REALLY FAST 2GB USB flash memory stick and plug it in a ReadyBoost.


Regards: tf1

 

[cdogg]

...it cannot use much more than 3 GB anyway

That's not the best stereotype to pass along to others. Although XP won't see much more than 3GB, the computer as a whole "can" use the entire 4GB. On average, about 600-800MB is reserved for the hardware. You can bet that a good chunk of that is being used in a modern computer. So to say installing more than 3GB is a waste isn't necessarily true in ALL situations.

Without messing with Windows XP's default settings, only 2GB of RAM can be used by applications. But don't stop there necessarily, because a portion of RAM is always going to the Windows kernel. So if you only had 2GB installed, a big chunk is being taken away from apps to be reserved for the kernel. That's why having more than 2GB installed can still help applications that need it.

There was a recent discussion on this:
thread602-1452884

In case you're thinking about the /3GB switch or other tweaks to get around the 2GB limitation, realize the risk of hurting system performance in other areas. I highly recommend you avoid it unless you are using a program like Adobe CS2/CS3 that suggests you do so.

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Einstein
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[cdogg]

So having said all that, the real question is do you need more than 2GB installed? On a laptop, I doubt that you do. The other guys have explained above why dual-channel isn't an option at 3GB when you only have 2 memory slots.

Sometime down the road as DDR3 SODIMMs become available, dual-channel won't be as much of a necessity.

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Einstein
[tab][navy]For posting policies, click [/navy]here.

 

[blackranger]

Thanks for the feedback guys. I think I see the picture a little clearer. It still seems strange though why so many laptops are coming from the manufacturer with 3GB RAM. Is it just to suck people like me in that just automatically think, oh, 3GB is better than 2GB, I must want that...

To answer your question about what I need more RAM for...
I want to get the most out of the NVidia 8800GTS video card installed in the laptop. I want to get as many fps as possible. Here are some examples of the laptops I'm talking about, the first one is the one I'm leaning towards but after your comments, I may just find a laptop with 2GB of RAM.

http://www.gateway.com/systems/product/529667906.php

http://www.notebookreview.com/default.asp?newsID=4208

http://www.alienware.com/Configurat...Code=PC-LT-AREA51M15X-AI1&SubCode=SKU-DEFAULT

note: on the alienware laptop, 4GB of RAM is an option, but as we know, the 512mb video card will reduce the available RAM to 3.5!! Surely this won't run in dual channel, right.

But why would Alienware, one of the highest end gaming computer companies want to do something that will hinder performance? Is dual channel not as important if you have 3.5GB of RAM to work with?

I just want to know what is the best setup to get the most frames per second for the least money in a portable system.

thanks...

 

[blackranger]

I just wanted to add one more link to a HP laptop that has 4GB RAM and is not so pricey. It has the 8600GT video card and a little less screen resolution but it seems like a decent deal if this whole 4GB of RAM thing is actually a good thing...

http://cgi.ebay.com/New-HP-Pavilion...goryZ177QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[cdogg]

Realize that a gaming version is generally a pimped-out laptop. But to desktops, they are typically no match for a lot of reasons:

[ul][li]slower components such as the FSB, hard drive, etc.[/li]
[li]complementing the slower specs, each component is a power-saving version of its desktop counterpart (the design focuses on the right balance between performance and power)[/li]
[li]more expensive[/li]
[li]harder to upgrade with fewer options[/li][/ul]

If gaming is your main concern, you should be spending your money on the ultimate desktop not laptop.

It still seems strange though why so many laptops are coming from the manufacturer with 3GB RAM

Actually one thing that is often overlooked is the fact that the frontside bus (FSB) is slower on a laptop processor. For example, there are a lot of dual-core centrinos out there that run on a 667MHz system bus. Well, PC2-5300 RAM also runs at 667MHz. There is no need to have dual-channel enabled since the memory speed already matches the system bus speed. So as a result, there is no penalty in having mismatched pairs.

note: on the alienware laptop, 4GB of RAM is an option, but as we know, the 512mb video card will reduce the available RAM to 3.5!! Surely this won't run in dual channel, right.

No, I think you may have missed a few points discussed in that thread I linked to above. It's not a one-to-one ratio. A 512MB video card is not going to steal 512MB of RAM. The GPU has it's own subsystem that is separate from the rest of your PC. In fact, your PC doesn't care about the type of memory or the amount of memory on the GPU.

Back in the old days, all integrated graphics shared system RAM, especially on laptops. Today, most of them have their own memory integrated right on the motherboard!

__________________________________________


A lot of people will tell you that matching the memory speed with the system bus is not all that important, and for the most part they're right. This is why you see a lot of laptops being sold today that pay no attention to dual-channel.

However, it's my personal opinion that you should always strive to get them to match for the best efficiency and lowest latency. When you can't do that, follow Alienware's example and make sure the memory bandwidth exceeds the system bus, and not the other way around like Gateway is doing in that first link you posted.

 

[cdogg]

I looked over your links just now, and among those four I would pick either the Alienware or the HP.

Keep this in mind...
The HP's 8600M GS is a low-to-mid range performer. All three of Alienware's options are faster, but the 8800M GTX completely crushes the competition. It will more than double the performance of the 8600M in a lot of benchmarks!!

For the price, the HP isn't bad. Just realize that the processor, hard drive, and GPU is not going to come close to the Alienware laptop you were looking at.

Then again, the HP is over $1000 cheaper!

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Einstein
[tab][navy]For posting policies, click [/navy]here.

 

[blackranger]

Thanks cdogg for taking the time to spell that out for me.
This is where I got the idea of the GPU taking away from the available RAM...

http://www.vistaclues.com/reader-question-32-bit-vista-memory-limits/

(quote from the link)
"Sucks, eh? As you probably read in this post, the “4GB” maximum memory limit of 32-bit Windows is purely theoretical. In practice, the max memory is something significantly less, equal to 4GB minus your video card memory and the address space allocated to a couple other hardware resourcse. Typically, the realistic maximum memory is somewhere betwee 2.5GB and 3.5GB."


Anyway, I can only afford either a desktop or laptop, and my job keeps me on the road and living out of hotels constantly, so I need a laptop to study and work. I was hoping to be able to find a laptop that I could game on as well so I could windown a bit and get some entertainment when I'm hanging out in those cheap hotels. I don't have $3500 for an Alienware PC and it seems that anything short of that isn't going to be able to handle games that well. I'm pretty bummed out and I guess I'm just am going to have to deal with reality and settle for a $800 dollar laptop that can take care of my office related work and just grow up and stop playing games.

thanks for your comments

 

[cdogg]

Well now that you've given a little more insight, I think the HP would suit you well. The 8600M GS is great for casual gaming - it will play the latest at decent speeds.

The Alienware is obviously for the enthusiast that puts gaming above all else. The 8800M GTX option here is a good investment for the long term, but would be overkill in your situation.

________________________________________


As for that Q&A on vistaclues.com...

It's a really, really short version of what's going on. In fact, it's only one paragraph! It would have been best to leave out "video card memory" to avoid confusion, because it's not clear how much impact the amount of video memory really has. From what I've read, the PCI-E interface is what hogs a lot of the address space and not so much the card itself.

Truthfully, you rarely need much more than 2GB anyway. Any exceptions to that would probably not involve a laptop or the 32-bit version of Windows!!

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Einstein
[tab][navy]For posting policies, click [/navy]here.

 

[blackranger]

thanks again,

It seems you really are an authority on this topic, so now that you know my situation, would you mind saying what you think is going to be a better gaming performer?...

the HP:

http://cgi.ebay.com/New-HP-Pavilion...goryZ177QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or the Gateway:

http://www.gateway.com/systems/product/529667905.php

If you have any other suggestions, I would definetly be open, however these are the best products I seem to be able to find for the money.

 

[wahnula]

Gateway has 8800 not 8600 graphics like the HP, the most important feature to a gamer, so if you are looking for a "gaming performer" it's the right choice. You can always add more RAM, swap out the HDD etc. in the future but you'll always be stuck with second-best graphics with the 8600 on the HP.

cdogg, you never cease to amaze me. Since I can't give you a dog biscuit, here's a star. Woof!



Tony

Users helping Users...

 

[Sympology]

Can I clear up a few points.

32 bit systems can ADDRESS 4gb of RAM, regardless if it is your Main memory, on the Video card, in your modem, on your crappy PCI > ISA card.
Now that does not mean if your card has 512mb of onborad RAM your system automatically has only 3.5 free.

Putting it very simply It can only use 4gb of ADDRESS SPACE at any time. So if your graphics card is using 512mb of ADDRESS space, that leaves 3.5 free for everything else (it gets even more complex, but on won't explain here).

Now you can use the /PAE switch to allow up to 64gb of RAM, but the apps must be written to allow this (SQL server for example), otherwise it's ignored.

The key is not to confuse RAM with ADDRESS SPACE. You can have 5tb of RAM, but as a rule, you can still only use 4gb of it.

This article is pretty good at explaining.

http://www.brianmadden.com/content/article/The-4GB-Windows-Memory-Limit-What-does-it-really-mean-

Only the truly stupid believe they know everything.
Stu.. 2004

 

[blackranger]

Thanks wahnula and StuReeves for your feedback.

I read alot of that article StuReeves, although I had to search for it with the heading because the link doesn't work. However I didn't see any talk about RAM running in dual channel.

Let me ask you this, if I'm looking for laptop that can put out the most fps, what is the best scenario when it comes to the onboard RAM that is installed on a 32 bit OS...

2 x 1GB modules running in dual channel
1 x 2GB module and 1 x 1GB module unable to run in dual channel
or
2 x 2GB modules running (Am I correct in saying that this format can't run in dual channel because the OS will only recognize 3GB to 3.5GB RAM due to the kernel requiring address space?) (But if that is so, when you have 2 x 1GB modules running dual channel, why doesn't the OS recognize less than 2GB due to the kernel requiring some of this RAM?)

I'm probably annoying you guys with my ignorance so feel free to just say, "get lost" and I'll stop.

 

[Freestone]

To save others the need to look up the link...

The 4GB Windows Memory Limit: What does it really mean?

http://www.brianmadden.com/content/content.asp?id=69

 

[Nelviticus]

The size of the RAM modules doesn't affect how fast they are, so 2 x 1GB modules will run just as fast as 2 x 2GB of the same rated speed. However, the machine itself may run faster when you have more memory - or more accurately, it's less likely to encounter a situation where a RAM shortage will slow it down.

Dual-channel will beat single-channel.

If money were no object I'd go for 2 x 2GB - there's no down-side other than cost (and maybe slightly reduced battery life due to increased power requirements, and maybe a little more heat too).

If you're on the road a lot you might want to look into how much the whole thing weighs. You can have either light or powerful!

One final point is that the graphics chip and the CPU will have far more impact on performance than RAM speed.

Regards

Nelviticus

 

[blackranger]

Thanks for the helpful info Nelviticus.
I don't mind luggin around weight and in most situatons I will have a power outlet available.

4GB it is with the 8800 GTX video. Should be smokin...