diff --git a/common/Darwin/DarwinMisc.cpp b/common/Darwin/DarwinMisc.cpp
index 400c26c9b5..5f12d186f7 100644
--- a/common/Darwin/DarwinMisc.cpp
+++ b/common/Darwin/DarwinMisc.cpp
@@ -50,6 +50,27 @@ u64 GetPhysicalMemory()
 	return getmem;
 }
 
+u64 GetAvailablePhysicalMemory()
+{
+	const mach_port_t host_port = mach_host_self();
+	vm_size_t page_size;
+
+	if (host_page_size(host_port, &page_size) != KERN_SUCCESS)
+		return 0;
+
+	vm_statistics64_data_t vm_stat;
+	mach_msg_type_number_t host_size = sizeof(vm_statistics64_data_t) / sizeof(integer_t);
+
+	if (host_statistics64(host_port, HOST_VM_INFO, reinterpret_cast<host_info64_t>(&vm_stat), &host_size) != KERN_SUCCESS)
+		return 0;
+
+	const u64 free_pages = static_cast<u64>(vm_stat.free_count);
+	const u64 inactive_pages = static_cast<u64>(vm_stat.inactive_count);
+	const u64 get_available_mem = (free_pages + inactive_pages) * page_size;
+
+	return get_available_mem;
+}
+
 static mach_timebase_info_data_t s_timebase_info;
 static const u64 tickfreq = []() {
 	if (mach_timebase_info(&s_timebase_info) != KERN_SUCCESS)
diff --git a/common/HostSys.h b/common/HostSys.h
index f79c36fb70..08eb31232c 100644
--- a/common/HostSys.h
+++ b/common/HostSys.h
@@ -181,10 +181,7 @@ private:
 extern u64 GetTickFrequency();
 extern u64 GetCPUTicks();
 extern u64 GetPhysicalMemory();
-#ifdef _WIN32
-// TODO: Someone do linux/mac.
 extern u64 GetAvailablePhysicalMemory();
-#endif
 /// Spin for a short period of time (call while spinning waiting for a lock)
 /// Returns the approximate number of ns that passed
 extern u32 ShortSpin();
diff --git a/common/Linux/LnxMisc.cpp b/common/Linux/LnxMisc.cpp
index acefebe701..2ef073932b 100644
--- a/common/Linux/LnxMisc.cpp
+++ b/common/Linux/LnxMisc.cpp
@@ -15,6 +15,7 @@
 
 #include <dbus/dbus.h>
 #include <spawn.h>
+#include <sys/sysinfo.h>
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -40,6 +41,15 @@ u64 GetPhysicalMemory()
 	return pages * getpagesize();
 }
 
+u64 GetAvailablePhysicalMemory()
+{
+	struct sysinfo info;
+	if (sysinfo(&info) != 0)
+		return 0;
+
+	return static_cast<u64>(info.freeram) * info.mem_unit;
+}
+
 u64 GetTickFrequency()
 {
 	return 1000000000; // unix measures in nanoseconds
diff --git a/pcsx2/CDVD/ThreadedFileReader.cpp b/pcsx2/CDVD/ThreadedFileReader.cpp
index 550b2794a7..1e9d9273aa 100644
--- a/pcsx2/CDVD/ThreadedFileReader.cpp
+++ b/pcsx2/CDVD/ThreadedFileReader.cpp
@@ -266,12 +266,11 @@ bool ThreadedFileReader::Precache2(ProgressCallback* progress, Error* error)
 
 bool ThreadedFileReader::CheckAvailableMemoryForPrecaching(u64 required_size, Error* error)
 {
-#ifdef _WIN32
 	// We want to check available physical memory instead of total.
 	const u64 memory_available = GetAvailablePhysicalMemory();
 	// Reserve 2GB of available memory for headroom.
 	constexpr u64 memory_reserve = 2147483648;
-	const u64 max_precache_size = std::max(0LL, static_cast<s64>(memory_available - memory_reserve));
+	const u64 max_precache_size = std::max(s64{0}, static_cast<s64>(memory_available - memory_reserve));
 
 	if (required_size > max_precache_size)
 	{
@@ -280,20 +279,6 @@ bool ThreadedFileReader::CheckAvailableMemoryForPrecaching(u64 required_size, Er
 			(required_size + memory_reserve) / _1gb);
 		return false;
 	}
-#else
-	// Don't allow precaching to use more than 50% of system memory.
-	// Hopefully nobody's running 2-4GB potatoes anymore....
-	const u64 memory_size = GetPhysicalMemory();
-	const u64 max_precache_size = memory_size / 2;
-
-	if (required_size > max_precache_size)
-	{
-		Error::SetStringFmt(error,
-			TRANSLATE_FS("CDVD", "Required memory ({}GB) is the above the maximum allowed ({}GB)."),
-			required_size / _1gb, max_precache_size / _1gb);
-		return false;
-	}
-#endif
 
 	return true;
 }