diff --git a/drivers/video/tdfxfb.c b/drivers/video/tdfxfb.c
index 77aafcf..fa7cbec 100644
--- a/drivers/video/tdfxfb.c
+++ b/drivers/video/tdfxfb.c
@@ -426,7 +426,7 @@
 	if (dev_id < PCI_DEVICE_ID_3DFX_VOODOO5) {
 		/* Banshee/Voodoo3 */
 		chip_size = 2;
-		if (has_sgram && (draminit0 & DRAMINIT0_SGRAM_TYPE))
+		if (has_sgram && !(draminit0 & DRAMINIT0_SGRAM_TYPE))
 			chip_size = 1;
 	} else {
 		/* Voodoo4/5 */