diff --git a/src/vgahooks.c b/src/vgahooks.c
index 7c229ba..33e017b 100644
--- a/src/vgahooks.c
+++ b/src/vgahooks.c
@@ -5,6 +5,9 @@
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
 #include "bregs.h" // set_fail
+#include "biosvar.h" // GET_GLOBAL
+#include "pci.h" // pci_find_device
+#include "pci_ids.h" // PCI_VENDOR_ID_VIA
 #include "util.h" // handle_155f
 #include "config.h" // CONFIG_*
 
@@ -26,11 +29,72 @@ handle_155f02(struct bregs *regs)
     set_success(regs);
 }
 
+static int
+getFBSize()
+{
+    /* Find K8M890 */
+    int bdf = pci_find_device(PCI_VENDOR_ID_VIA, 0x3336);
+    if (bdf < 0)
+        goto err;
+
+    /* FB config */
+    u8 reg = pci_config_readb(bdf, 0xa1);
+
+    /* GFX disabled ? */
+    if (!(reg & 0x80))
+        goto err;
+
+    static u8 mem_power[] = {0, 3, 4, 5, 6, 7, 8, 9};
+    return GET_GLOBAL(mem_power[(reg >> 4) & 0x7]);
+err:
+    return 5; // 32M frame buffer
+}
+
+static int
+getRamSpeed()
+{
+    int bdf = pci_find_device(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MEMCTL);
+    if (bdf < 0)
+        goto err;
+
+    /* mem clk 0 = DDR2 400 */
+    u8 reg = pci_config_readb(bdf, 0x94) & 0x7;
+    return reg + 7;
+err:
+    dprintf(1, "Warning: Memory clock speed is hardcoded\n");
+    return 4; // MCLK = DDR266
+}
+
+/* ECX = unknown/dont care
+   EBX[3..0] FB size 1 = 8MB 2=16MB ...
+   EBX[7..4] Memory speed:
+       0: SDR  66Mhz
+       1: SDR 100Mhz
+       2: SDR 133Mhz
+       3: DDR 100Mhz (PC1600 or DDR200)
+       4: DDR 133Mhz (PC2100 or DDR266)
+       5: DDR 166Mhz (PC2700 or DDR333)
+       6: DDR 200Mhz (PC3200 or DDR400)
+       Guesses (confirmed)
+       7: DDR2 100Mhz (DDR2 400)
+       8: DDR2 133Mhz (DDR2 533)
+       9: DDR2 166Mhz (DDR2 667)
+       A: DDR2 200Mhz (DDR2 800)
+       B: DDR2 233Mhz (DDR2 1066)
+       C: and above: Unknown
+   EBX[?..8] Total memory size?
+   EAX = 0x5f for success
+
+    K8M890 BIOS wants only this call (Desktop NoTv)
+*/
+
 static void
 handle_155f18(struct bregs *regs)
 {
     regs->eax = 0x5f;
-    regs->ebx = 0x545; // MCLK = 133, 32M frame buffer, 256 M main memory
+    u32 ramspeed = getRamSpeed();
+    u32 fbsize = getFBSize();
+    regs->ebx = 0x500 | (ramspeed << 4) | fbsize;
     regs->ecx = 0x060;
     set_success(regs);
 }