diff --git a/parallel-rdp/interface.cpp b/parallel-rdp/interface.cpp
index 46dd2af..819c4c4 100644
--- a/parallel-rdp/interface.cpp
+++ b/parallel-rdp/interface.cpp
@@ -62,6 +62,7 @@ static int cmd_cur;
 static int cmd_ptr;
 static bool emu_running;
 static GFX_INFO gfx_info;
+static uint32_t region;
 
 static const unsigned cmd_len_lut[64] = {
 	1,
@@ -330,34 +331,6 @@ bool rdp_update_screen()
 	return emu_running;
 }
 
-static uint32_t viCalculateHorizonalWidth(uint32_t hstart, uint32_t xscale)
-{
-	uint32_t start = (hstart >> 16) & 0x3FF;
-	uint32_t end = (hstart & 0x3FF);
-	uint32_t delta;
-	if (end > start)
-		delta = end - start;
-	else
-		delta = 0;
-	uint32_t scale = (xscale & 0xFFF);
-
-	return (delta * scale) / 0x400;
-}
-
-static uint32_t viCalculateVerticalHeight(uint32_t vstart, uint32_t yscale)
-{
-	uint32_t start = (vstart >> 16) & 0x3FF;
-	uint32_t end = (vstart & 0x3FF);
-	uint32_t delta;
-	if (end > start)
-		delta = end - start;
-	else
-		delta = 0;
-	uint32_t scale = (yscale & 0xFFF);
-
-	return (delta * scale) / 0x800;
-}
-
 uint64_t rdp_process_commands()
 {
 	uint64_t interrupt_timer = 0;
@@ -406,6 +379,7 @@ uint64_t rdp_process_commands()
 	while (cmd_cur - cmd_ptr < 0)
 	{
 		uint32_t w1 = cmd_data[2 * cmd_cur];
+		uint32_t w2 = cmd_data[2 * cmd_cur + 1];
 		uint32_t command = (w1 >> 24) & 63;
 		int cmd_length = cmd_len_lut[command];
 
@@ -418,21 +392,21 @@ uint64_t rdp_process_commands()
 		if (command >= 8)
 			processor->enqueue_command(cmd_length * 2, &cmd_data[2 * cmd_cur]);
 
+		if (RDP::Op(command) == RDP::Op::SetScissor)
+		{
+			uint32_t upper_left_x = ((w1 >> 12) & 0xFFF) >> 2;
+			uint32_t upper_left_y = (w1 & 0xFFF) >> 2;
+			uint32_t lower_right_x = ((w2 >> 12) & 0xFFF) >> 2;
+			uint32_t lower_right_y = (w2 & 0xFFF) >> 2;
+			region = (lower_right_x - upper_left_x) * (lower_right_y - upper_left_y);
+		}
 		if (RDP::Op(command) == RDP::Op::SyncFull)
 		{
 			processor->wait_for_timeline(processor->signal_timeline());
 
-			uint32_t width = viCalculateHorizonalWidth(*gfx_info.VI_H_START_REG, *gfx_info.VI_X_SCALE_REG);
-			if (width == 0)
-			{
-				width = 320;
-			}
-			uint32_t height = viCalculateVerticalHeight(*gfx_info.VI_V_START_REG, *gfx_info.VI_Y_SCALE_REG);
-			if (height == 0)
-			{
-				height = 240;
-			}
-			interrupt_timer = width * height;
+			interrupt_timer = region;
+			if (interrupt_timer == 0)
+				interrupt_timer = 5000;
 		}
 
 		cmd_cur += cmd_length;
diff --git a/parallel-rdp/interface.hpp b/parallel-rdp/interface.hpp
index 306d3c8..ba8832c 100644
--- a/parallel-rdp/interface.hpp
+++ b/parallel-rdp/interface.hpp
@@ -16,10 +16,6 @@ extern "C"
 		uint32_t *DPC_START_REG;
 		uint32_t *DPC_END_REG;
 		uint32_t *DPC_STATUS_REG;
-		uint32_t *VI_H_START_REG;
-		uint32_t *VI_V_START_REG;
-		uint32_t *VI_X_SCALE_REG;
-		uint32_t *VI_Y_SCALE_REG;
 	} GFX_INFO;
 
 	void rdp_init(void *_window, GFX_INFO _gfx_info, bool _upscale, bool _integer_scaling, bool _fullscreen);
diff --git a/src/device/ai.rs b/src/device/ai.rs
index db98341..8cc0607 100644
--- a/src/device/ai.rs
+++ b/src/device/ai.rs
@@ -111,7 +111,7 @@ pub fn read_regs(
     _access_size: device::memory::AccessSize,
 ) -> u32 {
     let reg = (address & 0xFFFF) >> 2;
-    match reg as u32 {
+    let return_value = match reg as u32 {
         AI_LEN_REG => {
             let value = get_remaining_dma_length(device);
             if value < device.ai.last_read {
@@ -128,7 +128,9 @@ pub fn read_regs(
             value as u32
         }
         _ => device.ai.regs[reg as usize],
-    }
+    };
+    device::cop0::add_cycles(device, 20);
+    return_value
 }
 
 pub fn write_regs(device: &mut device::Device, address: u64, value: u32, mask: u32) {
diff --git a/src/device/cart/sc64.rs b/src/device/cart/sc64.rs
index 4f831ce..8adb1cf 100644
--- a/src/device/cart/sc64.rs
+++ b/src/device/cart/sc64.rs
@@ -37,6 +37,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     if device.sc64.regs_locked {
         return 0;
     }
diff --git a/src/device/mi.rs b/src/device/mi.rs
index c48b491..81f02d7 100644
--- a/src/device/mi.rs
+++ b/src/device/mi.rs
@@ -53,6 +53,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     device.mi.regs[((address & 0xFFFF) >> 2) as usize]
 }
 
diff --git a/src/device/pi.rs b/src/device/pi.rs
index c02826c..691411e 100644
--- a/src/device/pi.rs
+++ b/src/device/pi.rs
@@ -40,6 +40,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     let reg = (address & 0xFFFF) >> 2;
     match reg as u32 {
         PI_WR_LEN_REG | PI_RD_LEN_REG => 0x7F,
diff --git a/src/device/rdp.rs b/src/device/rdp.rs
index 3e826c0..9df454c 100644
--- a/src/device/rdp.rs
+++ b/src/device/rdp.rs
@@ -53,6 +53,7 @@ pub fn read_regs_dpc(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     let reg = (address & 0xFFFF) >> 2;
     match reg as u32 {
         DPC_STATUS_REG => {
@@ -131,6 +132,7 @@ pub fn read_regs_dps(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     device.rdp.regs_dps[((address & 0xFFFF) >> 2) as usize]
 }
 
diff --git a/src/device/rdram.rs b/src/device/rdram.rs
index 9132c6f..37d2615 100644
--- a/src/device/rdram.rs
+++ b/src/device/rdram.rs
@@ -73,6 +73,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     let chip_id = (address >> 13) & 3;
     let reg = (address & 0x3FF) >> 2;
     match reg as u32 {
diff --git a/src/device/ri.rs b/src/device/ri.rs
index 55ae22b..60056b4 100644
--- a/src/device/ri.rs
+++ b/src/device/ri.rs
@@ -20,6 +20,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     if ((address & 0xFFFF) >> 2) as u32 == RI_SELECT_REG && !device.ri.ram_init {
         device::cop0::add_cycles(device, device.cpu.clock_rate / 2); // hack, simulate RDRAM initialization
         device.ri.ram_init = true;
diff --git a/src/device/rsp_interface.rs b/src/device/rsp_interface.rs
index 60d1ce8..1c643ca 100644
--- a/src/device/rsp_interface.rs
+++ b/src/device/rsp_interface.rs
@@ -101,8 +101,10 @@ pub fn read_mem_fast(
 pub fn read_mem(
     device: &mut device::Device,
     address: u64,
-    _access_size: device::memory::AccessSize,
+    access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, access_size as u64 / 4);
+
     let masked_address = address as usize & RSP_MEM_MASK;
     u32::from_be_bytes(
         device.rsp.mem[masked_address..masked_address + 4]
@@ -264,6 +266,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     let reg = (address & 0xFFFF) >> 2;
     match reg as u32 {
         SP_DMA_BUSY_REG | SP_DMA_FULL_REG => {
@@ -321,6 +324,7 @@ pub fn read_regs2(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     device.rsp.regs2[((address & 0xFFFF) >> 2) as usize]
 }
 
diff --git a/src/device/si.rs b/src/device/si.rs
index df1e644..4751ebc 100644
--- a/src/device/si.rs
+++ b/src/device/si.rs
@@ -31,6 +31,7 @@ pub fn read_regs(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
+    device::cop0::add_cycles(device, 20);
     device.si.regs[((address & 0xFFFF) >> 2) as usize]
 }
 
diff --git a/src/device/vi.rs b/src/device/vi.rs
index 3f3d9d8..9b825e2 100644
--- a/src/device/vi.rs
+++ b/src/device/vi.rs
@@ -12,11 +12,11 @@ const VI_CURRENT_REG: u32 = 4;
 const VI_V_SYNC_REG: u32 = 6;
 const VI_H_SYNC_REG: u32 = 7;
 //const VI_LEAP_REG: u32 = 8;
-pub const VI_H_START_REG: u32 = 9;
-pub const VI_V_START_REG: u32 = 10;
+//const VI_H_START_REG: u32 = 9;
+//const VI_V_START_REG: u32 = 10;
 //const VI_V_BURST_REG: u32 = 11;
-pub const VI_X_SCALE_REG: u32 = 12;
-pub const VI_Y_SCALE_REG: u32 = 13;
+//const VI_X_SCALE_REG: u32 = 12;
+//const VI_Y_SCALE_REG: u32 = 13;
 pub const VI_REGS_COUNT: u32 = 14;
 
 pub struct Vi {
@@ -89,6 +89,7 @@ pub fn read_regs(
     if reg as u32 == VI_CURRENT_REG {
         set_current_line(device)
     }
+    device::cop0::add_cycles(device, 20);
     device.vi.regs[reg as usize]
 }
 
diff --git a/src/ui/video.rs b/src/ui/video.rs
index ac039ad..ee4000d 100644
--- a/src/ui/video.rs
+++ b/src/ui/video.rs
@@ -33,10 +33,6 @@ pub fn init(device: &mut device::Device, fullscreen: bool) {
         DPC_START_REG: &mut device.rdp.regs_dpc[device::rdp::DPC_START_REG as usize],
         DPC_END_REG: &mut device.rdp.regs_dpc[device::rdp::DPC_END_REG as usize],
         DPC_STATUS_REG: &mut device.rdp.regs_dpc[device::rdp::DPC_STATUS_REG as usize],
-        VI_H_START_REG: &mut device.vi.regs[device::vi::VI_H_START_REG as usize],
-        VI_V_START_REG: &mut device.vi.regs[device::vi::VI_V_START_REG as usize],
-        VI_X_SCALE_REG: &mut device.vi.regs[device::vi::VI_X_SCALE_REG as usize],
-        VI_Y_SCALE_REG: &mut device.vi.regs[device::vi::VI_Y_SCALE_REG as usize],
     };
 
     unsafe {