diff --git a/pcsx2/GS/Renderers/Common/GSDevice.cpp b/pcsx2/GS/Renderers/Common/GSDevice.cpp
index 491ef692d1..d43c0927b1 100644
--- a/pcsx2/GS/Renderers/Common/GSDevice.cpp
+++ b/pcsx2/GS/Renderers/Common/GSDevice.cpp
@@ -387,38 +387,25 @@ void GSDevice::Interlace(const GSVector2i& ds, int field, int mode, float yoffse
 		default:
 			m_current = m_merge;
 	}
-
-	if ((GSConfig.FXAA || GSConfig.ShadeBoost) && m_current != m_merge)
-	{
-		const GSVector2i s = m_current->GetSize();
-		ResizeTexture(&m_merge, GSTexture::Type::RenderTarget, s.x, s.y, false);
-		StretchRect(m_current, GSVector4(0, 0, 1, 1), m_merge, GSVector4(0, 0, ds.x, ds.y), ShaderConvert::COPY, false);
-		m_current = m_merge;
-	}
 }
 
 void GSDevice::FXAA()
 {
-	const GSVector2i s = m_current->GetSize();
-
-	if (ResizeTexture(&m_target_tmp, GSTexture::Type::RenderTarget, s.x, s.y, false))
+	// Combining FXAA+ShadeBoost can't share the same target.
+	GSTexture*& dTex = (m_current == m_target_tmp) ? m_merge : m_target_tmp;
+	if (ResizeTexture(&dTex, GSTexture::Type::RenderTarget, m_current->GetWidth(), m_current->GetHeight(), false, true))
 	{
-		const GSVector4 sRect(0, 0, 1, 1);
-		const GSVector4 dRect(0, 0, s.x, s.y);
-
-		StretchRect(m_current, sRect, m_target_tmp, dRect, ShaderConvert::TRANSPARENCY_FILTER, false);
-		DoFXAA(m_target_tmp, m_current);
+		InvalidateRenderTarget(dTex);
+		DoFXAA(m_current, dTex);
+		m_current = dTex;
 	}
 }
 
 void GSDevice::ShadeBoost()
 {
-	const GSVector2i s = m_current->GetSize();
-
-	if (ResizeTexture(&m_target_tmp, GSTexture::Type::RenderTarget, s.x, s.y, false))
+	if (ResizeTexture(&m_target_tmp, GSTexture::Type::RenderTarget, m_current->GetWidth(), m_current->GetHeight(), false, true))
 	{
-		const GSVector4 sRect(0, 0, 1, 1);
-		const GSVector4 dRect(0, 0, s.x, s.y);
+		InvalidateRenderTarget(m_target_tmp);
 
 		// predivide to avoid the divide (multiply) in the shader
 		const float params[4] = {
@@ -427,8 +414,9 @@ void GSDevice::ShadeBoost()
 			static_cast<float>(GSConfig.ShadeBoost_Saturation) * (1.0f / 50.0f),
 		};
 
-		StretchRect(m_current, sRect, m_target_tmp, dRect, ShaderConvert::COPY, false);
-		DoShadeBoost(m_target_tmp, m_current, params);
+		DoShadeBoost(m_current, m_target_tmp, params);
+
+		m_current = m_target_tmp;
 	}
 }