Hardware Secrets
Home | Audio | Case | Cooling | CPU | Input | Memory | Mobile | Motherboard | Networking | Power | Storage | Video | Other
Content
Articles
First Look
News
Reviews
Tutorials
Main Menu
About Us
Compare Prices
Datasheets
Dictionary
Download
Drivers
Forums
Gabriel's Blog
Links
Manufacturer Finder
Newsletter
On The Web
RSS Feed
Test Your Skills
Newsletter
Subscribe today!
Search




Recommended Book
Maximum PC Guide to Extreme PC Mods (Maximum PC Guide To...)
By Jon Phillips
Que
Price: $29.99

Home » Video
SLI vs. CrossFire
Author: Gabriel Torres
Type: Articles Last Updated: April 15, 2008
Page: 5 of 8
$ Check REAL-TIME pricing for VisionTek RADEON HD 4850, (512 MB) PCI Express Video Card $
Dell: $199.99 CompUSA.com: $184.99
TigerDirect.com: $184.99 Buy.com: $197.55
Compuvest: $219.71 Bestbuy: $185.99

CrossFire

Of course nVidia’s rival ATI couldn’t stay behind and released an equivalent technology to work with video cards based on ATI chips. The main advantage of CrossFire over SLI is that on CrossFire the video cards don’t need to be based on the same graphics chip (GPU) – but there are some limitations to what cards can be used together, as will explain in details (basically the cards can be different but must be from the same family).

CrossFire can use the following modes to render images:

  • Scissors: This mode is similar to the SFR (Split Frame Rendering) from SLI, but since you can hook two different video cards under CrossFire, the half of the screen rendered by the fastest video card would be done first and the card would have to wait for the slower can to finish its job to go ahead to the next frame. This would make the faster video card work at the same speed of the slower one. To solve this problem, Crossfire enables dynamic load balancing, i.e. if a fast card is connected together with a slower one, the system won’t divide the screen as two equal parts, it will put the faster card to render a bigger portion of the screen than the slower one, thus making them to finish the rendering at the same time.
  • SuperTiling: Under this mode the screen is divided into several small squared portions (or “tiles”), each one measuring 32x32 pixels, and each video card is in charge of handling part of the available tiles. Load balancing is also used here, so the fastest card will get more tiles to render than the slowest card if you use two different video cards.
  • Alternate Frame Rendering (AFR): this mode is identical to the SLI mode with the same name, where while one video card is rendering the current frame, the other card is rendering the next frame.
  • Super AA: Equivalent to SLI AA, this mode allows increase image quality instead of performance. You can increase AA (anti-aliasing) up to x14 under this mode.

Just like SLI, CrossFire is available only to PCI Express cards and you need to have a motherboard with two (or four, in the case of CrossFireX) x16 PCI Express slots and the motherboard must be based on an AMD/ATI or Intel chipset. Keep in mind that depending on the chipset the x16 PCI Express slots can run at x8 speed when CrossFire mode is enabled (more on this later).

Also when CrossFire mode is enabled only one video output is available, so you can’t have a multiple monitor configuration under CrossFire, just a single display.

So far there are three CrossFire generations: CrossFire, Native CrossFire and CrossFireX.

The first generation of CrossFire had two main problems. First they required a “master” card, called “CrossFire Edition”, which was different from the regular model sold around – it had an additional chip called “compositing engine”. For example, there was Radeon X850 CrossFire Edition and the regular Radeon X850 XT video card. You couldn’t use two Radeon X850 XT cards, one of them needed to be the special CrossFire edition.

The second major problem was that you needed an external cable to connect the video cards, as you can see on Figure 7. This cable connects the DVI output from the “slave” card to a connector called DMS-59 (or DMS for short), which has the same physical size of DVI but with more pins, or to a connector called VHDCI (Very High Density Cable Interconnect), which is a connector originally used by some SCSI devices, on the “master” card.

This version of CrossFire can increase the maximum resolution of your video card up to 2560x1600, the same limit of SLI.

CrossFire
click to enlarge
Figure 7: First generation CrossFire cards were connected thru an external cable.

DMS vs. VHDCI
click to enlarge
Figure 8: DMS-59 (left) and VHDCI (right) connectors, which can be found on master (“CrossFire Edition”) cards.

As we mentioned before even though on CrossFire the video cards don’t need to be the same, there is a list of video cards that can be hooked together, as you can see on the table below. Basically the “slave” card must be from the same family from the “master card”. So if you have a Radeon 1900 CrossFire edition you cannot install a Radeon X1800 XL to form a CrossFire system, for example.

First Video CardSecond Video CardConnector
Radeon X1950 CrossFire Edition
Radeon X1900 CrossFire Edition
Radeon X1950 XTX
Radeon X1950 XT
Radeon X1900 XTX
Radeon X1900 XT

VHDCI

Radeon X1800 CrossFire EditionRadeon X1800 XT
Radeon X1800 XL
Radeon X1800 GTO

VHDCI

Radeon X850 CrossFire EditionRadeon X850 XT Platinum Edition
Radeon X850 XT
Radeon X850 Pro

DMS-59

Radeon X800 CrossFire EditionRadeon X800 XT Platinum Edition
Radeon X800 XT
Radeon X800 XL
Radeon X800 Pro
Radeon X800

DMS-59

 
Pages (8): « 1 2 3 4 [5] 6 7 8 »
Print Version | Send to Friend | | Bookmark Article | Comments (4)

Related Content
  • ECS SDGE Technology
  • HIS Radeon X800 GT IceQ II Review
  • XFX GeForce 6200 TurboCache 64 MB 64-bit Review
  • ATI Radeon HD 2600 XT Review
  • ASUS M3A32-MVP DeLuxe/WiFi-AP Motherboard

  • Recommended Deals
    ATI RADEON® 9550, (256 MB) AGP Video Card


    CompUSA.com: $29.99 CompuVest: $49.00
    eBay: $26.00 TigerDirect.com: $29.99
    Circuitcity: $76.99
    eVGA e-GeForce® 7600 GT, (512 MB) AGP Video Card


    TigerDirect.com: $109.99 CompUSA.com: $109.99
    PNY GeForce® 7600 GS, (512 MB) AGP Video Card


    eBay: $130.00 Server Supply: $225.00
    CompuVest: $92.00
    PNY GeForce® 8600 GT, (256 MB) PCI Express Video Card


    Server Supply: $110.00 eBay: $67.40
    CompuVest: $49.99 J&R Music and Computer World: $93.99
    eVGA e-GeForce FX 5500, (256 MB) AGP Video Card


    CompuVest: $34.25 TigerDirect.com: $39.99
    CompUSA.com: $39.99 Now Direct: $41.88
    Egoodz: $99.99 Riverton Studios: $45.00

    RSSLatest News
    Patriot Launches SO-DIMM DDR3-2000
    September 5, 2008 - 7:28 AM PST
    Kingston Unveils HyperX SO-DIMM Memory Kit
    September 4, 2008 - 10:59 AM PST
    Thermaltake Launches V9 Case Series
    September 3, 2008 - 7:54 AM PST
    Sigma Launches 1,000 W Power Supply
    September 2, 2008 - 7:55 AM PST
    Intel Launches New Processors
    September 1, 2008 - 11:16 AM PST
    Scythe Launches Kaze Maru Case Fan
    September 1, 2008 - 10:24 AM PST
    Lian Li Launches Silent Force Power Supply Series
    August 29, 2008 - 9:24 AM PST
    New Thermaltake Power Supplies
    August 28, 2008 - 11:43 AM PST
    Sparkle and MSI Launch GeForce 9400 GT
    August 28, 2008 - 11:13 AM PST
    NZXT Unveils Whisper Full Tower Case
    August 28, 2008 - 10:39 AM PST
    .:: More News ::.

    RSSLatest Content
    Everything You Need to Know About the CPU C-States Power Saving Modes
    AMD ATI Chips Comparison Table
    nVidia Chips Comparison Table
    Inside Intel Nehalem Microarchitecture
    OCZ Elixir Gaming Keyboard Review
    Everything You Need to Know About The QuickPath Interconnect (QPI)
    Me and Woz
    Introduction to Wireless USB (WUSB)
    Nikon Coolpix S600 Camera Review
    IDF Fall 2008: Opening Keynote
    Thecus N5200 NAS Review
    ECS GeForce 9800 GTX+ Hydra Video Card Review
    320 GB Hard Disk Drive Round-Up
    Razer Destructor Mouse Pad Review
    Sapphire HD 4870 X2 Video Card Review

    Our Most Popular Articles
    Maximum CPU Temperature
    772,534 views
    nVidia Chips Comparison Table
    480,558 views
    AMD ATI Chips Comparison Table
    425,799 views
    ATI Radeon X1300 Pro Review
    413,947 views
    ATI Radeon X1600 XT Review
    408,703 views
    How to Find Out Your Motherboard Manufacturer and Model
    385,449 views
    Connecting Two PCs Using a USB-USB Cable
    348,002 views
    How To Correctly Apply Thermal Grease
    333,254 views
    Sempron vs. Athlon XP
    280,177 views
    Sempron 3400+ Review
    270,381 views

    Latest Threads in Our Forums
    Flip Ultra Camcorder
    by Hardware Secrets Team
    2.1 PC speakers in car
    by rajani1983
    How to conect spdif on my nvidia 9600 gt with x-fi extreme gamer spdif
    by yapyap
    Review - Logitech X530 (5.1)
    by tomahawk 1705
    Slipstreaming SP3
    by BedCommando
    powercolor x1650 pro agp problem
    by jedsky
    Building PC for Audio.
    by Wall'E
    What configuration is better??
    by Gabriel Torres
    Upgrading to dual core
    by Gabriel Torres
    Patriot Launches SO-DIMM DDR3-2000
    by Hardware Secrets Team
    .:: Visit Our Forums ::.

    © 2004-8, Hardware Secrets, LLC. All rights reserved.
    Advertising | Legal Information | Privacy Policy
    All times are Pacific Standard Time (PST, GMT -08:00)