diff --git a/application/pages/InstanceSettingsPage.cpp b/application/pages/InstanceSettingsPage.cpp
index 82438583..22dbd81f 100644
--- a/application/pages/InstanceSettingsPage.cpp
+++ b/application/pages/InstanceSettingsPage.cpp
@@ -11,12 +11,15 @@
 
 #include <java/JavaInstallList.h>
 #include <FileSystem.h>
+#include <sys.h>
 
 InstanceSettingsPage::InstanceSettingsPage(BaseInstance *inst, QWidget *parent)
 	: QWidget(parent), ui(new Ui::InstanceSettingsPage), m_instance(inst)
 {
 	m_settings = inst->settings();
 	ui->setupUi(this);
+	auto sysMB = Sys::getSystemRam() / Sys::megabyte;
+	ui->maxMemSpinBox->setMaximum(sysMB);
 	loadSettings();
 }
 
diff --git a/application/pages/global/JavaPage.cpp b/application/pages/global/JavaPage.cpp
index 543cc11f..f43fd641 100644
--- a/application/pages/global/JavaPage.cpp
+++ b/application/pages/global/JavaPage.cpp
@@ -30,6 +30,7 @@
 #include "settings/SettingsObject.h"
 #include <FileSystem.h>
 #include "MultiMC.h"
+#include <sys.h>
 
 JavaPage::JavaPage(QWidget *parent) : QWidget(parent), ui(new Ui::JavaPage)
 {
@@ -40,6 +41,8 @@ JavaPage::JavaPage(QWidget *parent) : QWidget(parent), ui(new Ui::JavaPage)
 	resizer->addWidgetsFromLayout(ui->javaSettingsGroupBox->layout(), 0);
 	resizer->addWidgetsFromLayout(ui->customCommandsGroupBox->layout(), 0);
 
+	auto sysMB = Sys::getSystemRam() / Sys::megabyte;
+	ui->maxMemSpinBox->setMaximum(sysMB);
 	loadSettings();
 }
 
diff --git a/application/setupwizard/JavaWizardPage.cpp b/application/setupwizard/JavaWizardPage.cpp
index 46b6ee3f..50f61681 100644
--- a/application/setupwizard/JavaWizardPage.cpp
+++ b/application/setupwizard/JavaWizardPage.cpp
@@ -22,7 +22,7 @@
 JavaWizardPage::JavaWizardPage(QWidget *parent)
 	:BaseWizardPage(parent)
 {
-	m_availableMemory = Sys::getSystemRam() / (1024ull * 1024ull);
+	m_availableMemory = Sys::getSystemRam() / Sys::megabyte;
 
 	goodIcon = MMC->getThemedIcon("status-good");
 	yellowIcon = MMC->getThemedIcon("status-yellow");
diff --git a/libraries/systeminfo/include/sys.h b/libraries/systeminfo/include/sys.h
index 36f7d9cd..e40d9a92 100644
--- a/libraries/systeminfo/include/sys.h
+++ b/libraries/systeminfo/include/sys.h
@@ -3,6 +3,7 @@
 
 namespace Sys
 {
+const uint64_t megabyte = 1024ull * 1024ull;
 struct KernelInfo
 {
 	QString kernelName;