Sign in with
Sign up | Sign in
Your question

Question about SLi/Xfire and Video Ram

Last response: in Systems
Share
July 7, 2008 2:36:17 PM

I am building a new machine and have decided to go with NVidia as my GPU...

Currently I'm leaning towards dual 9800's. Screw the 280GTX! It's Performance / Value ratio is near zero if you ask me...

However, there ARE two features I'll be giving up by getting dual 9800's instead of the 280GTX...

First is the PhysX functionality that is built into the 280GTX. the 9800's don't have it. No big deal... I will just add in an Ageia card.

The second item I'm giving up is Video ram. The 280GTX has 1Gig and the 9800's typically have 512 Megs...

But if I run 2 9800's in SLi mode, do I add the ram together? Does it work that way? (512 Meg + 512 Meg = 1 Gig?)

- Witt
July 7, 2008 2:57:38 PM

"Performance / Value ratio is near zero" - the performance is definitely good, so you think the value is near infinite, right? :) 

No you don't add the RAM together in SLI, it's still 512MB.

I would recommend an X38 or X48 motherboard, with either a single 9800GX2 or two HD 4870. Either way, try to avoid getting an nVidia motherboard. nVidia seems to have a bit of a quality problem these days. If you haven't heard, their stock dropped 30% last Friday after an announcement of that sort.
July 7, 2008 3:37:36 PM

I don't know anyone with a 680/780i problem, SLI works good on mine. RAM does not get added.

Now, you are wrong about one thing. nVidia has beta physics software out for the 9800, which has been reported to be very effective. So good news there. Also, later you can get even more performance from tri-SLI.
Related resources
July 7, 2008 3:38:24 PM

aevm said:
"Performance / Value ratio is near zero" - the performance is definitely good, so you think the value is near infinite, right? :) 

Heh! You know what I mean. :) 

aevm said:
No you don't add the RAM together in SLI, it's still 512MB.

Thanks, I did not know that. However, how soon do you think we'll be needing 1 Gig of Video ram? 512 Megs is a lot of textures! Think I'll be missing out if I run with 512?
aevm said:
I would recommend an X38 or X48 motherboard, with either a single 9800GX2 or two HD 4870. Either way, try to avoid getting an nVidia motherboard. nVidia seems to have a bit of a quality problem these days. If you haven't heard, their stock dropped 30% last Friday after an announcement of that sort.

I hear that... No Nvidia chipset on the motherboard for me, thank you! I was thinking about a MSI P35 Neo2-FR. I will look into the X38 and X48 Motherboards... I think I'm going to run a Q9450 Core 2 Quad in it.

As for the Video Cards... Isn't the 9800GX2 about $400? The HD 4870 is about $300. With 2 of em that's $600 just for the GPU's... OUCH! On the other hand, the GPU isn't the place you wanna start cutting corners. :) 

- Witt
July 7, 2008 3:41:16 PM

themyrmidon said:
I don't know anyone with a 680/780i problem, SLI works good on mine. RAM does not get added.

Are you implying that running 2+ GeForce cards in SLi mode can only be done with an NVideo chipset on your motherboard? If that is the case... I was un-aware and will probably look into X-Fire.

- Witt
July 7, 2008 3:43:04 PM

themyrmidon said:
I don't know anyone with a 680/780i problem, SLI works good on mine. RAM does not get added.

Now, you are wrong about one thing. nVidia has beta physics software out for the 9800, which has been reported to be very effective. So good news there. Also, later you can get even more performance from tri-SLI.


1. The nVidia chipset problems have been well documented, and admitted by nVidia.
2. Tri-SLI seems to serve the primary purpose of looking good in the case and generating heat, the functional advantage is minimal at best. A foolish thing to recommend to someone who is concerned about Performance for Value.
July 7, 2008 3:47:25 PM

Witt78 said:
Are you implying that running 2+ GeForce cards in SLi mode can only be done with an NVideo chipset on your motherboard? If that is the case... I was un-aware and will probably look into X-Fire.

- Witt


I think a little research is in order prior to spending your money. Yes, to run SLI you have to have an nVidia chipset SLI mobo. For Xfire you need an Intel chipset mobo, and for max performance the X38 or X48 chipset boards. Personally I would recommend the Gigabyte X38 or X48 boards, good layout, excellent i/o.
July 7, 2008 4:09:43 PM

rgsaunders said:
I think a little research is in order prior to spending your money. Yes, to run SLI you have to have an nVidia chipset SLI mobo. For Xfire you need an Intel chipset mobo, and for max performance the X38 or X48 chipset boards. Personally I would recommend the Gigabyte X38 or X48 boards, good layout, excellent i/o.


Yes, I am in my research phase right now. Yes, I need to educate myself before I start buying parts. The last machine I built was a Pentium 3 @ 500 Mhz, so it's been quite a while.

QUESTION... What is the major difference between the X38 and X48 chipsets?

- Witt
July 7, 2008 4:36:16 PM

X48 is an X38 with official support for fsb 1600 and higher binned. It may also have more options in the BIOS, depending on manufacturer and model. In general, there's no major difference IMO.
July 7, 2008 4:53:34 PM

aevm said:
X48 is an X38 with official support for fsb 1600 and higher binned. It may also have more options in the BIOS, depending on manufacturer and model. In general, there's no major difference IMO.


At the moment I'm looking at an ASUS RAMPAGE FORMULA LGA 775 Intel X48 ATX Motherboard.

At $290 it's twice what I wanted to pay, but looks like a very good board.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131284

Does the 6 SATA2 connectors mean I can have a 6 drive RAID 0? Wow, that would be Titts on Fire!

- Witt
July 7, 2008 5:23:19 PM

Yuck, 6 drives in RAID 0 means 6 times more chance than usual that some drive will fail and you lose all files. You also realize that RAID 0 improves only the access time for large files, right? Finding small files will still be done at the regular speed of a single drive.

But yeah, you're right, 6 SATA connectors means you can have 6 drives. I'd reserve one for a DVD burner.

July 7, 2008 5:49:50 PM

aevm said:
Yuck, 6 drives in RAID 0 means 6 times more chance than usual that some drive will fail and you lose all files. You also realize that RAID 0 improves only the access time for large files, right? Finding small files will still be done at the regular speed of a single drive.

But yeah, you're right, 6 SATA connectors means you can have 6 drives. I'd reserve one for a DVD burner.


Drive failure is a pretty rare occurance isn't it? (I've never had an ATA drive go out on me... Except for that time my power supply blew up and fried my whole system.) How reliable are the SATA/300 drives these days?

Also... Is SATA really needed for a DVD burner? I was going to place 2 cd drives onto the IDE interface... Is that a bad idea?

- Witt

July 7, 2008 5:59:00 PM

It is rare, true, if you buy good disks. Avoid Seagate's 7200.11 320GB for example, or Samsung Spinpoint F1. Those seem to get more complaints than others. Avoid WD's 500GB disks (WD5000AAKS) too, they're reliable but slow.

A DVD burner will work just as well if it's IDE, no speed difference. You'll just have to worry about jumpers a bit and enable IDE in the BIOS (depends on MB) and deal with a wide cable and make sure it doesn't block airflow. Nothing major IMO.

I don't know if it's OK to put two opticals on the same IDE header. Never tried it myself. Maybe it's just fine as long as you don't use them at the same time. Hopefully somebody can tell us.

July 7, 2008 6:33:40 PM

Hard disk failure is a case of when rather than if normally, that is why it is foolish to entrust your data to a raid 0 configuration. For a normal recreational user of computers, raid 0 is neither necessary nor desirable. I have seen many hard drives fail, from the full spectrum of manufacturers. Properly configured and administered raid configurations can be useful for the professional user, normally they are a vanity toy for the home user. Proper backup procedures will protect your data far better than raid will.
July 7, 2008 6:55:08 PM

aevm said:
A DVD burner will work just as well if it's IDE, no speed difference. You'll just have to worry about jumpers a bit and enable IDE in the BIOS (depends on MB) and deal with a wide cable and make sure it doesn't block airflow. Nothing major IMO.

I think I'm going to buy some of those rounded IDE cables for this build. I'm dropping $3000 on this build, why not grab some cables too. :) 

aevm said:
I don't know if it's OK to put two opticals on the same IDE header. Never tried it myself. Maybe it's just fine as long as you don't use them at the same time. Hopefully somebody can tell us.

That is correct. It just slipped my mind... It will work fine, until I try to do a disc duplication.

Two optical drives on one IDE will work. But not at the same time.

- Witt
July 7, 2008 7:03:58 PM

rgsaunders said:
Hard disk failure is a case of when rather than if normally, that is why it is foolish to entrust your data to a raid 0 configuration. For a normal recreational user of computers, raid 0 is neither necessary nor desirable. I have seen many hard drives fail, from the full spectrum of manufacturers. Properly configured and administered raid configurations can be useful for the professional user, normally they are a vanity toy for the home user. Proper backup procedures will protect your data far better than raid will.


Like I said before... I have never had a drive fail on me, except when I had a power supply blow up. And that incident fried my entire PC. :fou: 

Also... I am the type of person that formats his machine once every 12-24 months, then installs a fresh copy of Windows... I find that it keeps my computer running smooth.

Sometime in the first 12 months of getting this PC, I will buy a large external drive to backup anything that would be annoying to loose. MP3's and what not...

Plus!

If I get 4 250 Gig SATA/300 7200's for $43 each, and you get one 750 Gig drive for $200... My drive will be 25% larger, 4X faster, and $28 cheaper than yours... I'd hardly call that foolish.

- Witt
July 7, 2008 7:32:23 PM

Your drive will be 4x faster on reading/writing large files, but exactly as fast or less when dealing with small files or fragmented files. It will also make more noise and heat. Also, if your 250GB drives don't have perpendicular recording, they might be only 2x faster than a good $130 WD7500AAKS even for large files. You really need to do some research here before you buy, lots of traps waiting...

Edit: how about a more interesting type of RAID, like 5 or 10? You'd get both improved speed and data safety.
July 7, 2008 7:45:03 PM

LOL. Very funny read. The things people invent, wow...
July 8, 2008 6:14:42 AM

Read the SLI/CF FAQ,it will help u alot:
http://www.tomshardware.co.uk/forum/245454-15-crossfire...

Do SLI or CrossFire double the memory ?
This is one the questions that many people make mistake understanding it .
The answer is NO , SLI or CrossFire doesnt double the memory , You have a 512MB card , adding another card wont make your memory 1GB, it still will be 512MB
Another example :
A game needs 512MB card to run at maximum settings , and you have a 256MB card , and you think if you add another 256MB card , your memory will be 512MB and thats not true.

You may see this mistake in many sites.
!