diff --git a/core/strconv/fast_float.odin b/core/strconv/fast_float.odin
index 0fcf597d6..d1a45d952 100644
--- a/core/strconv/fast_float.odin
+++ b/core/strconv/fast_float.odin
@@ -28,7 +28,7 @@ _ :: bits // needed for STRCONV_FAST_FLOAT=false
 
 /*
 	Disable with `-define:STRCONV_FAST_FLOAT=false` to drop the Eisel-Lemire step
-	and its table.
+	and its table, and to read digits one at a time (instead of eight).
 */
 FAST_FLOAT :: #config(STRCONV_FAST_FLOAT, true)
 
@@ -183,7 +183,9 @@ parse_number_string :: #force_inline proc "contextless" (s: string) -> (mantissa
 	if i < n && s[i] == '.' {
 		i += 1
 		frac_start := i
-		i, mantissa = loop_parse_if_eight_digits(s, i, mantissa)
+		when FAST_FLOAT {
+			i, mantissa = loop_parse_if_eight_digits(s, i, mantissa)
+		}
 		for i < n && s[i] - '0' <= 9 {
 			mantissa = mantissa*10 + u64(s[i] - '0')
 			i += 1
diff --git a/core/strconv/hex_float.odin b/core/strconv/hex_float.odin
index a6dffd9a3..5dab19fcd 100644
--- a/core/strconv/hex_float.odin
+++ b/core/strconv/hex_float.odin
@@ -36,15 +36,17 @@ scan_hex_float :: proc "contextless" (s: string) -> (mantissa: u64, exp: int, ne
 		saw_digits ||= s[i] == '0'
 		i += 1
 	}
-	for i+8 <= n && nd+8 <= MAX_HEX_DIGITS {
-		v := read8_to_u64(s, i)
-		if !is_eight_hex_digits(v) {
-			break
+	when FAST_FLOAT {
+		for i+8 <= n && nd+8 <= MAX_HEX_DIGITS {
+			v := read8_to_u64(s, i)
+			if !is_eight_hex_digits(v) {
+				break
+			}
+			mantissa = mantissa<<32 | parse_eight_hex_digits(v)
+			nd += 8
+			i += 8
+			saw_digits = true
 		}
-		mantissa = mantissa<<32 | parse_eight_hex_digits(v)
-		nd += 8
-		i += 8
-		saw_digits = true
 	}
 	for i < n {
 		d := hex_digit_table[s[i]]
@@ -76,27 +78,29 @@ scan_hex_float :: proc "contextless" (s: string) -> (mantissa: u64, exp: int, ne
 				i += 1
 			}
 		}
-		for i+8 <= n && nd+8 <= MAX_HEX_DIGITS {
-			v := read8_to_u64(s, i)
-			if !is_eight_hex_digits(v) {
-				break
-			}
-			mantissa = mantissa<<32 | parse_eight_hex_digits(v)
-			nd += 8
-			exp -= 32
-			i += 8
-			saw_digits = true
-		}
-		if i+4 <= n && nd+4 <= MAX_HEX_DIGITS {
-			// Four digits: pad them with "0000" and use the 8-digit code.
-			v := u64(read4_to_u32(s, i)) | 0x3030_3030 << 32
-			if is_eight_hex_digits(v) {
-				mantissa = mantissa<<16 | parse_eight_hex_digits(v) >> 16
-				nd += 4
-				exp -= 16
-				i += 4
+		when FAST_FLOAT {
+			for i+8 <= n && nd+8 <= MAX_HEX_DIGITS {
+				v := read8_to_u64(s, i)
+				if !is_eight_hex_digits(v) {
+					break
+				}
+				mantissa = mantissa<<32 | parse_eight_hex_digits(v)
+				nd += 8
+				exp -= 32
+				i += 8
 				saw_digits = true
 			}
+			if i+4 <= n && nd+4 <= MAX_HEX_DIGITS {
+				// Four digits: pad them with "0000" and use the 8-digit code.
+				v := u64(read4_to_u32(s, i)) | 0x3030_3030 << 32
+				if is_eight_hex_digits(v) {
+					mantissa = mantissa<<16 | parse_eight_hex_digits(v) >> 16
+					nd += 4
+					exp -= 16
+					i += 4
+					saw_digits = true
+				}
+			}
 		}
 		for i < n {
 			d := hex_digit_table[s[i]]
diff --git a/core/strconv/strconv.odin b/core/strconv/strconv.odin
index 7b7a9ce50..dbae1efe6 100644
--- a/core/strconv/strconv.odin
+++ b/core/strconv/strconv.odin
@@ -974,24 +974,28 @@ parse_float_prefix_generic :: proc($T: typeid, str: string) -> (value: T, nr: in
 		i := 2
 		// Read 8 hex digits at a time, then 4 digits at a time (like "0h3c00" or groups
 		// between `_` separators), then single digits and `_` separators.
-		for i+8 <= len(str) {
-			v := read8_to_u64(str, i)
-			if !is_eight_hex_digits(v) {
-				break
+		when FAST_FLOAT {
+			for i+8 <= len(str) {
+				v := read8_to_u64(str, i)
+				if !is_eight_hex_digits(v) {
+					break
+				}
+				as_int = as_int<<32 | parse_eight_hex_digits(v)
+				digits += 8
+				i += 8
 			}
-			as_int = as_int<<32 | parse_eight_hex_digits(v)
-			digits += 8
-			i += 8
 		}
 		for i < len(str) {
-			if i+4 <= len(str) {
-				// Four digits: pad them with "0000" and use the 8-digit code.
-				v := u64(read4_to_u32(str, i)) | 0x3030_3030 << 32
-				if is_eight_hex_digits(v) {
-					as_int = as_int<<16 | parse_eight_hex_digits(v) >> 16
-					digits += 4
-					i += 4
-					continue
+			when FAST_FLOAT {
+				if i+4 <= len(str) {
+					// Four digits: pad them with "0000" and use the 8-digit code.
+					v := u64(read4_to_u32(str, i)) | 0x3030_3030 << 32
+					if is_eight_hex_digits(v) {
+						as_int = as_int<<16 | parse_eight_hex_digits(v) >> 16
+						digits += 4
+						i += 4
+						continue
+					}
 				}
 			}
 			if str[i] != '_' {