diff --git a/src/BizHawk.Common/Extensions/SpanSplit.cs b/src/BizHawk.Common/Extensions/SpanSplit.cs
index 9fc43a4a76..167e01abde 100644
--- a/src/BizHawk.Common/Extensions/SpanSplit.cs
+++ b/src/BizHawk.Common/Extensions/SpanSplit.cs
@@ -5,16 +5,13 @@
  * and https://github.com/dotnet/runtime/blob/v9.0.0/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/ValueListBuilder.cs
  */
 
-#if !NET8_0_OR_GREATER
+#if !NET9_0_OR_GREATER
 #pragma warning disable RS0030 // `Debug.Assert` w/o message, breaks BizHawk convention
 #pragma warning disable SA1514 // "Element documentation header should be preceded by blank line"
 
 using System.Buffers;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
-#if NETCOREAPP3_0_OR_GREATER
-using System.Runtime.Intrinsics;
-#endif
 
 namespace BizHawk.Common
 {
@@ -534,13 +531,6 @@ namespace BizHawk.Common
 				sep0 = separators[0];
 				sep1 = separators.Length > 1 ? separators[1] : sep0;
 				sep2 = separators.Length > 2 ? separators[2] : sep1;
-#if NETCOREAPP3_0_OR_GREATER
-				if (Vector128.IsHardwareAccelerated && source.Length >= Vector128<ushort>.Count * 2)
-				{
-					MakeSeparatorListVectorized(source, ref sepListBuilder, sep0, sep1, sep2);
-					return;
-				}
-#endif
 
 				for (int i = 0; i < source.Length; i++)
 				{
@@ -583,120 +573,6 @@ namespace BizHawk.Common
 			}
 		}
 
-#if NETCOREAPP3_0_OR_GREATER
-		private static void MakeSeparatorListVectorized(ReadOnlySpan<char> sourceSpan, ref ValueListBuilder<int> sepListBuilder, char c, char c2, char c3)
-		{
-			// Redundant test so we won't prejit remainder of this method
-			// on platforms where it is not supported
-			if (!Vector128.IsHardwareAccelerated)
-			{
-				throw new PlatformNotSupportedException();
-			}
-			Debug.Assert(sourceSpan.Length >= Vector128<ushort>.Count);
-			nuint lengthToExamine = (uint)sourceSpan.Length;
-			nuint offset = 0;
-			ref char source = ref MemoryMarshal.GetReference(sourceSpan);
-
-			if (Vector512.IsHardwareAccelerated && lengthToExamine >= (uint)Vector512<ushort>.Count*2)
-			{
-				Vector512<ushort> v1 = Vector512.Create((ushort)c);
-				Vector512<ushort> v2 = Vector512.Create((ushort)c2);
-				Vector512<ushort> v3 = Vector512.Create((ushort)c3);
-
-				do
-				{
-					Vector512<ushort> vector = Vector512.LoadUnsafe(ref source, offset);
-					Vector512<ushort> v1Eq = Vector512.Equals(vector, v1);
-					Vector512<ushort> v2Eq = Vector512.Equals(vector, v2);
-					Vector512<ushort> v3Eq = Vector512.Equals(vector, v3);
-					Vector512<byte> cmp = (v1Eq | v2Eq | v3Eq).AsByte();
-
-					if (cmp != Vector512<byte>.Zero)
-					{
-						// Skip every other bit
-						ulong mask = cmp.ExtractMostSignificantBits() & 0x5555555555555555;
-						do
-						{
-							uint bitPos = (uint)BitOperations.TrailingZeroCount(mask) / sizeof(char);
-							sepListBuilder.Append((int)(offset + bitPos));
-							mask = BitOperations.ResetLowestSetBit(mask);
-						} while (mask != 0);
-					}
-
-					offset += (nuint)Vector512<ushort>.Count;
-				} while (offset <= lengthToExamine - (nuint)Vector512<ushort>.Count);
-			}
-			else if (Vector256.IsHardwareAccelerated && lengthToExamine >= (uint)Vector256<ushort>.Count*2)
-			{
-				Vector256<ushort> v1 = Vector256.Create((ushort)c);
-				Vector256<ushort> v2 = Vector256.Create((ushort)c2);
-				Vector256<ushort> v3 = Vector256.Create((ushort)c3);
-
-				do
-				{
-					Vector256<ushort> vector = Vector256.LoadUnsafe(ref source, offset);
-					Vector256<ushort> v1Eq = Vector256.Equals(vector, v1);
-					Vector256<ushort> v2Eq = Vector256.Equals(vector, v2);
-					Vector256<ushort> v3Eq = Vector256.Equals(vector, v3);
-					Vector256<byte> cmp = (v1Eq | v2Eq | v3Eq).AsByte();
-
-					if (cmp != Vector256<byte>.Zero)
-					{
-						// Skip every other bit
-						uint mask = cmp.ExtractMostSignificantBits() & 0x55555555;
-						do
-						{
-							uint bitPos = (uint)BitOperations.TrailingZeroCount(mask) / sizeof(char);
-							sepListBuilder.Append((int)(offset + bitPos));
-							mask = BitOperations.ResetLowestSetBit(mask);
-						} while (mask != 0);
-					}
-
-					offset += (nuint)Vector256<ushort>.Count;
-				} while (offset <= lengthToExamine - (nuint)Vector256<ushort>.Count);
-			}
-			else if (Vector128.IsHardwareAccelerated)
-			{
-				Vector128<ushort> v1 = Vector128.Create((ushort)c);
-				Vector128<ushort> v2 = Vector128.Create((ushort)c2);
-				Vector128<ushort> v3 = Vector128.Create((ushort)c3);
-
-				do
-				{
-					Vector128<ushort> vector = Vector128.LoadUnsafe(ref source, offset);
-					Vector128<ushort> v1Eq = Vector128.Equals(vector, v1);
-					Vector128<ushort> v2Eq = Vector128.Equals(vector, v2);
-					Vector128<ushort> v3Eq = Vector128.Equals(vector, v3);
-					Vector128<byte> cmp = (v1Eq | v2Eq | v3Eq).AsByte();
-
-					if (cmp != Vector128<byte>.Zero)
-					{
-						// Skip every other bit
-						uint mask = cmp.ExtractMostSignificantBits() & 0x5555;
-						do
-						{
-							uint bitPos = (uint)BitOperations.TrailingZeroCount(mask) / sizeof(char);
-							sepListBuilder.Append((int)(offset + bitPos));
-							mask = BitOperations.ResetLowestSetBit(mask);
-						} while (mask != 0);
-					}
-
-					offset += (nuint)Vector128<ushort>.Count;
-				} while (offset <= lengthToExamine - (nuint)Vector128<ushort>.Count);
-			}
-
-			while (offset < lengthToExamine)
-			{
-				char curr = Unsafe.Add(ref source, offset);
-				if (curr == c || curr == c2 || curr == c3)
-				{
-					sepListBuilder.Append((int)offset);
-				}
-				offset++;
-			}
-		}
-#endif
-
 		/// <summary>
 		/// Uses ValueListBuilder to create list that holds indexes of separators in string.
 		/// </summary>