Need help with DDR2/DDR3 w/ 8400 GS

So I'm not really into the whole technical stuff... this is my first laptop, and my first time really buying a computer on my own. I just bought a 1420 with the nVidia 8400M GS, and I'm seeing a bunch of people get a $100 credit on the 8600. Two questions:

1) Does the same discount apply to the 8400? Meaning, do they advertise it as DDR3, but it really comes as DDR2?
2) Can someone explain the difference to me in the most basic of terms? I've looked around and found a couple things, but people jump right into units and numbers out of nowhere, and I just don't follow.

I don't know if anyone has gotten the 1420 and tested the GPU yet, so I'm not sure if we know. For reference, here's what the Dell site says about the 8400:

128MB discrete memory, 64-bit graphics memory interface, a graphics memory bandwidth of 9.6, and a texture fill rate of 3.2 billion/sec.

Sorry if this is a stupid question, but I'm all for getting as much money back as I can. And I'll be sure to rep whoever helps, of course...

 

DDR3 is faster memory than DDR2, and it's not RAM it's dedicated graphics memory. But yes, you can get a discount off the 8400GS as well because that was advertised as DDR3 as well

 

I know it's not RAM. I don't know why I put that.

Where does Dell say it's DDR3, though? I've seen the numbers explanation for the 8600, but not the 8400, and I'd like to at least appear to know what I'm talking about when I call.

Also, do we know for SURE that it's DDR2, or are we just assuming it is because the 8600 on the 1520 is DDR2?

 

The 8600M should be around twice as fast in games based on 3dmark06 benchmarks.

~1400 for 8400M and ~3000 for 8600M

People getting a $100 credit aren't getting a discount, per se. You could probably finaggle the $100 out of Dell but you can't honestly say you didn't know the graphics memory was lower than advertized at this point.

Bottom line- spring for the 8600M if you intend to game.

 

Check out this link for benchmarks...

http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html

And yes, it is absolutely going to be DDR2.

 

Discount, credit... free money.

And I'm getting the 1420, so no 8600 option for me. I think you misinterpreted my question... I'm not looking for the difference between the 8400 and 8600, but the DDR2 and DDR3 versions of the 8400.

 

It was purely some HIGH LEVEL persons mistake when creating the documentation. nVidia offers UP TO DDR3 memory for the 8-series, but also offers some DDR2 versions for reduced heat and power consumption. Dell engineers used the DDR2 version, but someone else composing all the technical documentation referenced nVidia's specifications and saw the DDR3 RAM. It's all just an honest mistake, which just happened to be very high level...

 

I'm not completely sure, but I think I read somewhere that the 8400M GS in both the M1330 and the 1420 are both DDR3 - unlike the 8600M GT. It's underclocked tho' at 500Mhz. I can't remember where - check out the recent 1420 threads.

 

My bad, good luck.

 

interesting... i'd like to get 100 back when i buy the 1420 lol

 

The VRAM is quite probably GDDR3 with these 8400M GS cards, however it is clocked at 500MHz instead of 600MHz as the spec sheet would indicate.

With a 64 bit memory bus and the 9.6GB/s advertised memory bandwidth, that implies:

(9600MBytes/s)/64bits*(8bits/byte) = 1200MHz DDR (or 600MHz)

Since they're actually coming clocked at 500MHz, you're technically getting lower memory bandwidth than they specify on their webpage. That's the loophole that has allowed a few people to get a credit.

 

where do you see the 500mhz? i went to the site and all it said was gddr3, 64bits, and 128mb memory.

 

if you test it with 3rd party programs, the speed shows as 500mhz. i think the part about the advertised memory bandwidth is on the 1520 page where it shows the diff between 8400gs and 8600gt

personally i just kinda gave up, its too much hassle and stress to get that $100 credit, as only some reps will give it to you =(

 

If the chip is clocked at 500mhz then it is ddr3. There was a post about this that walked you through how the numbers made sense, so i will repeat it to the best of my knowledge.

First what dell said about the 8400 card,
1) 64 bit memory interface
2) 9.6 gb/s bandwidth

This would imply it is ddr3 because the card would have to be clocked at 600mhz (you get this number by doing the opposite operations i am about to do).

600mhz * 2 [ddr = double data rate, so we multiply by 2]
1200 * 64 [64 bit memory interface]
76800 / 8 [8 bits in a byte]
9600 / 1000 [change mega to giga (1000 megaunits = 1 gigaunit)]
=9.6 gigbytes/second bandwidth.

As far as i know the fastest ddr2 runs at is 400mhz, without being overclocked. Because people have been recording 8.0 gb/s bandwidth, which translates into a 500mhz clock speed, the chip is still ddr3, but underclocked.

All this info is based on the Inspiron line of notebooks, because the xps never gave any info on the bandwidth of the cards. The bandwidth info has been removed from their site as of about a week ago, so don't bother looking.

Hope this helps.

 

No, there's nothing saying that if it's clocked faster than 400MHz, it's automatically GDDR3. There's really no point in even arguing GDDR2, GDDR3 as it makes little difference, it's the clock speed that matters and if you're going to argue something, argue that point.

 

Why do you say that? I only found out about this yesterday and I first ordered back in June.