Overclock.net › Forums › Graphics Cards › AMD/ATI › 7870 XT - To Crossfire or Not to Crossfire...That is the ?
New Posts  All Forums:Forum Nav:

7870 XT - To Crossfire or Not to Crossfire...That is the ?

post #1 of 7
Thread Starter 
I'm thinking about getting another Sapphire 7870 XT, and I have an older motherboard. I have to pick you guys' brain, I've got a P8P67 Le and looking up the specs this is what I see
1 x PCIe 2.0 x16 (blue) *1
1 x PCIe 2.0 x16 (x4 mode, black) *1

What does it mean when it says x4 mode? Also I have a 700 or 750 Watt PSU. Will that handle two cards?
Sorry, never crossfired before. How much of a difference will I notcie if I crossfire?

Thanks!
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
post #2 of 7
it means 1 slot is the full 16x and the other is only 4x its not good for crossfire if it were 8x/8x ok 16/4 not so good i would stick with that card until 8k series are out then buy one.
post #3 of 7
Quote:
Originally Posted by [CyGnus] View Post

it means 1 slot is the full 16x and the other is only 4x its not good for crossfire if it were 8x/8x ok 16/4 not so good i would stick with that card until 8k series are out then buy one.

I have to agree with him. The power supply is sufficient but the motherboard will not have the required bandwidth to get optimal performance.
My Gaming Rig
(16 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i5 2500K @ 4,5GHz - 1.296 volts MSI P67A-GD55 Asus Strix Geforce GTX 970 4GB Mushkin Enhanced Silverline Stiletto 2x4GB 1333... 
Hard DriveHard DriveHard DriveHard Drive
Seagate Barracuda 7200.12 1TB Seagate Barracuda 7200.12 500GB Toshiba HDKPC08 3TB Samsung 840 Evo 120GB 
CoolingOSMonitorKeyboard
Corsair Hydro Series H60 Windows 8.1 Professional x64 BenQ G2420HD 24" 1920x1080 IBM Model M2 French Canadian Layout '93 
PowerCaseMouseMouse Pad
Mushkin Enhanced Joule 1000W Modular Antec DF-35 (Modded) Razer Deathadder 3500 DPI Mionix Sargas 900 
  hide details  
Reply
My Gaming Rig
(16 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i5 2500K @ 4,5GHz - 1.296 volts MSI P67A-GD55 Asus Strix Geforce GTX 970 4GB Mushkin Enhanced Silverline Stiletto 2x4GB 1333... 
Hard DriveHard DriveHard DriveHard Drive
Seagate Barracuda 7200.12 1TB Seagate Barracuda 7200.12 500GB Toshiba HDKPC08 3TB Samsung 840 Evo 120GB 
CoolingOSMonitorKeyboard
Corsair Hydro Series H60 Windows 8.1 Professional x64 BenQ G2420HD 24" 1920x1080 IBM Model M2 French Canadian Layout '93 
PowerCaseMouseMouse Pad
Mushkin Enhanced Joule 1000W Modular Antec DF-35 (Modded) Razer Deathadder 3500 DPI Mionix Sargas 900 
  hide details  
Reply
post #4 of 7
Thread Starter 
Thanks guys, that's what I needed to know. +1 Snowmen, thanks Mod!
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
post #5 of 7
There is a 2.3% fps difference between 2.0 X8 and X4 on a 680 at 1920x1080. X4 would be fine for xt crossfire

http://tpucdn.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/images/bf3_1920_1200.gif
Core I7 5960X
(10 items)
 
  
CPUMotherboardGraphicsGraphics
Intel Core I7 5960X ASRock X99 OC Formula MSI GTX 970 Gaming MSI GTX 970 Gaming 
RAMHard DriveCoolingOS
G. Skill 16GB DDR4 2600 Sandisk Extreme II 240GB SSD Custom 480 Water Setup Windows 10 
PowerCase
AX1500I Corsair 900D 
  hide details  
Reply
Core I7 5960X
(10 items)
 
  
CPUMotherboardGraphicsGraphics
Intel Core I7 5960X ASRock X99 OC Formula MSI GTX 970 Gaming MSI GTX 970 Gaming 
RAMHard DriveCoolingOS
G. Skill 16GB DDR4 2600 Sandisk Extreme II 240GB SSD Custom 480 Water Setup Windows 10 
PowerCase
AX1500I Corsair 900D 
  hide details  
Reply
post #6 of 7
I've tried it, and its not an issue of bandwidth/performance, but rather compatibility. On one of my old rigs, my two 7850's worked flawlessly on a board with two PCIe 3.0 x8 slots. However when I put them in a board with one PCIe2.0 x8 and x4 slots, temporarily while I got a new board, there were so many issues I couldn't count. Random boots, black screening, pixelation, etc etc etc. Note only the mobo changed while the CPU and everything else remained the same. So it can cause some issues.
post #7 of 7
Thread Starter 
Yea I'm going to hold off, rather then hit some snags like JJ said. I could order the second card then have issues out the wazoo. Then have to pull it until I got a newer motherboard, and I wouldn't want to order a newer board without 3.0, then I'd have to upgrade my CPU to utilize it.
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
Sandy Rigster
(16 items)
 
Little Big Rig
(5 items)
 
 
CPUMotherboardGraphicsRAM
Intel Core i7 2600K @ 4.4 P8P67 LE Radeon R9 290 8gb 1600mhz  
Hard DriveHard DriveOSMonitor
WD Caviar Black Crucial M4  Windows 8.1 Pro x64 Asus 24" VS248H-P 
MonitorMonitorKeyboardPower
19" Hanspree 19" Hanspree Logitech G510 Cooler Master eXtreme Power Plus 700-Watt 
Mouse
Logitech G700 / Razer Death Adder 2013 
CPUGraphicsRAMOS
Intel Core 2 Quad Q6600 Ati Radeon HD 4770 OCZ Gold DDR2 800 Windows Vista Ultimate x64 
Monitor
Philips 42" LCD TV 2ms 120hz 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: AMD/ATI
Overclock.net › Forums › Graphics Cards › AMD/ATI › 7870 XT - To Crossfire or Not to Crossfire...That is the ?