XSPC RAZOR 4870/4890 Compatibility

Hello there.

I have Crossfire HD4870 on my Asus Maximus Extreme.
I am thinking on going With liquid cooling.
I have purchased a single Xspc Razor 4870 Water Block (non other was available at the time of purchase).
Now the store has only Xspc Razor 4890 Water block in stock.
Is it compatible to HD4870 Reference design?

Thanks in Advance.

No - see other post .... the PWM, Capacitors are different.